# Snow Day Calculator

> A free snow day calculator for U.S. ZIP codes, made for students, parents and school staff: the chance that schools close, start late or open as usual on the next school day, worked out from the live National Weather Service forecast by rules this site publishes.

An independent website: not a school, school district, state agency or government website, and not the National Weather Service. Only a school district decides whether its schools close. Published by PVV Media Technologies, Newton, Iowa. Free, no sign-up.

## How to get an answer for a ZIP code

- For people: https://snowdaycalculator.website/?zip=14201 (any five-digit U.S. ZIP code): the chance of a snow day, a late start and school as usual for the next school days, with the reasons.
- For programs: https://snowdaycalculator.website/api/chance/?zip=14201 answers in JSON (the same numbers). Please keep requests to what a reader asked for.

## How the calculator works

- It reads the [National Weather Service forecast](https://www.weather.gov/documentation/services-web-api) for the part of the ZIP code where most people live: snow and ice from 6 AM the day before to 3 PM on the school day (mostly given as 6-hour totals, shared evenly across their hours), the wind chill from 5 to 9 AM, and the winter alerts in force.
- Snow counts fully overnight (9 PM to 6 AM) and while buses run (6 to 10 AM), 80% in the afternoon and evening before, 45% during the school day and 35% the morning before; snow falling above freezing counts less.
- By the site's rule of thumb, the usual closing point (snow at which schools close about half the time) is 0.5 x (normal snowfall a year in inches)^0.7, between 0.5 and 15 inches; normal snowfall from [NOAA's 1991-2020 climate normals](https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals) at the nearest stations. About half an inch in Atlanta, 3 in Washington, 4 in Philadelphia, 6.5 in Chicago, 8 in Minneapolis, 8.5 in Boston, 11.5 in Buffalo.
- By the same rule of thumb, ice: about a tenth of an inch closes schools almost anywhere. Cold: the normal December-February low minus 45 F, between -60 F and 0 F. Weather Service warnings raise the chance a little (the snow or cold behind them is already counted), watches and advisories less; a Blizzard or Ice Storm Warning from 5 to 9 AM keeps the chance of a snow day at 65% or more. A late start counts only snow and ice before 10 AM.
- The answer is three chances that add up to 100%: snow day, late start, school as usual. [Every rule](https://snowdaycalculator.website/how-it-works/).

## The next school day right now

Worked out 3:37 PM EDT, Thursday for the 296 cities on the map (the largest in each state, and Washington, D.C.). None of them has even a 5% chance of a snow day on its next school day.

## Facts the guides rely on

- The Weather Service sets winter warning levels office by office: a winter storm warning means about 2 inches of snow around [Atlanta](https://www.weather.gov/ffc/winterweathersafety), 5 inches around [Baltimore and Washington](https://www.weather.gov/lwx/warningsdefined), 6 around [Boston](https://www.weather.gov/box/criteria) and 8 in 12 hours (or 10 in 24) in [northern Michigan](https://www.weather.gov/apx/winterdefinitions).
- Since October 1, 2024 the cold alerts are Extreme Cold Warning, Extreme Cold Watch and Cold Weather Advisory ([NWS](https://www.weather.gov/news/243009-cold-hazard-simplification)).
- Districts decide in the early morning: [Fairfax County, Virginia](https://www.fcps.edu/resources/safety-and-transportation/weather-cancellation-procedures) by about 4:30 AM; [Montgomery County, Maryland](https://www.montgomeryschoolsmd.org/emergency/closings/index.aspx) by 5 AM (or 7 PM the evening before); [Minneapolis](https://www.mpschools.org/about-mps/severe-weather) by 5:30 AM; [Milwaukee](https://milwaukeepublicschools.org/families/policies/weather) by 6 AM.
- Cold closings: [Saint Paul](https://www.spps.org/about/weather-plan) at a forecast wind chill of -35 F at 6 AM; [Kenosha](https://www.kusd.edu/board-education/policies/policy-3643-emergency-school-closings-and-or-learning-adjustments/) lists a sustained -30 F wind chill or -20 F among its reasons to close; [Buffalo](https://www.buffaloschools.org/article/1315907) will consider closing at -18 F.
- In Massachusetts, days with 10 inches or more of snow closed schools, while 4 to 10 inch days mostly did not but raised absences ([Goodman, NBER 2014](https://www.nber.org/papers/w20221)).

## Pages

- [Snow Day Calculator](https://snowdaycalculator.website/): the calculator, the map of the next school day and the questions people ask.
- [Snow Day Map: The Next School Day in 296 U.S. Cities](https://snowdaycalculator.website/snow-day-map/): The chance of a snow day on the next school day in 296 U.S. cities, each state's largest and Washington, D.C., from the National Weather Service forecast, updated every half hour.
- [Snow Days by State: Chances, Make-Up Days and Remote Days](https://snowdaycalculator.website/states/): Every state’s page: its cities’ chances for the next school day, how much snow falls there in a normal year, and what its own law says about make-up days and remote learning on snow days.
- [Snow Day Guides: How Schools Decide, Snow, Cold and Warnings](https://snowdaycalculator.website/guides/): How school districts decide on snow days, how much snow and cold close schools where you live, what the Weather Service’s warnings mean, and the difference between a snow day, a late start and an e-learning day.

## Guides

- [How Schools Decide Snow Days: Who Makes the Call, When and Why](https://snowdaycalculator.website/how-schools-decide-snow-days/): The superintendent decides, most often between 4:30 and 6 AM, after staff drive the roads from as early as 2 AM. Roads, timing, buses, cold, buildings and the forecast all count.
- [How Much Snow Does It Take to Close School? Inches by City](https://snowdaycalculator.website/how-much-snow-to-close-school/): It depends on where you live. By our rule of thumb, schools close about half the time at half an inch of snow in Atlanta and 11.5 inches in Buffalo. Timing and ice count too.
- [How Cold Is Too Cold for School? Wind Chill Rules Districts Use](https://snowdaycalculator.website/cold-weather-school-closings/): The districts we found that publish a number put it between −18°F and −35°F, mostly as wind chill. Others act on a Weather Service Extreme Cold Warning, which starts at 0°F near Atlanta.
- [Snow Day vs Two-Hour Delay vs E-Learning Day: What Each Means](https://snowdaycalculator.website/snow-day-vs-delay-vs-e-learning/): A snow day cancels school, a two-hour delay starts it late, an early dismissal ends it early and an e-learning day moves it online. What each means, and why districts pick one.
- [Winter Storm Watch vs Warning vs Advisory: What Each Alert Means](https://snowdaycalculator.website/winter-storm-watch-vs-warning/): A watch means a big winter storm is possible, an advisory means lesser snow or ice is coming, and a warning means a significant storm is expected. What each means for travel and school.
- [Snow Day Superstitions: The Rituals and What Really Closes School](https://snowdaycalculator.website/snow-day-superstitions/): Pajamas inside out, a spoon under the pillow, ice cubes down the toilet: fun rituals with no known origin that cannot change a forecast. Snow, ice, cold and your district decide.

## States (chances now, normal snowfall, make-up and remote-day rules)

- [Alabama Snow Day Calculator: Ice, Rare Snow and Make-Up Days](https://snowdaycalculator.website/alabama/): Snow is rare in Alabama, so little of it closes schools: by our rule of thumb half an inch to 1 inch, or about 0.08 inch of ice. Missed days must be made up to reach 180.
- [Alaska Snow Day Calculator: Chances, Cold and Emergency Days](https://snowdaycalculator.website/alaska/): Alaska schools close for heavy snow or extreme cold: about 6 to 12.5 inches of snow by our rule of thumb. The state’s education commissioner decides whether closed days count.
- [Arizona Snow Day Calculator: High-Country Snow and Closure Rules](https://snowdaycalculator.website/arizona/): Phoenix and Tucson average almost no snow, so by our rule of thumb half an inch would close schools there. Arizona’s snow falls up high: Flagstaff’s airport averages 90.1 inches a year.
- [Arkansas Snow Day Calculator: Ice, Snow, Make-Up Days and AMI](https://snowdaycalculator.website/arkansas/): By our rule of thumb, 1 to 2.5 inches of snow, or about a tenth of an inch of ice, closes Arkansas schools. Every district builds 5 make-up days, or 30 hours, into its calendar.
- [California Snow Day Calculator: Sierra Snow and the J-13A Form](https://snowdaycalculator.website/california/): California’s snow falls in the mountains, not in Los Angeles or San Diego. When a storm closes schools, a district can ask the state to excuse the lost days on Form J-13A.
- [Colorado Snow Day Calculator: Chances, Mountain Snow and School Hours](https://snowdaycalculator.website/colorado/): By our rule of thumb, 7 to 9 inches of snow closes schools in Colorado's big cities half the time. The state counts scheduled hours, with a small cushion for closings.
- [Connecticut Snow Day Calculator: Chances, Make-Ups and Remote Days](https://snowdaycalculator.website/connecticut/): By our rule of thumb, 6 to 8 inches of snow closes schools in Connecticut's big cities half the time. Make-up days can't fall on weekends, and remote learning can count.
- [Delaware Snow Day Calculator: Chances, Delays and School Hours](https://snowdaycalculator.website/delaware/): By our rule of thumb, about 3 to 4 inches of snow closes Delaware schools about half the time. The state counts hours, and a weather delay can be no longer than 2 hours.
- [Washington, D.C. Snow Day Calculator: Closings, Delays and Make-Up](https://snowdaycalculator.website/washington-dc/): By our rule of thumb, about 3 inches of snow closes schools in Washington, D.C. For DC Public Schools the Mayor decides, and some snow days, but not delays, are made up at year’s end.
- [Florida Snow Day Calculator: Rare Cold and Emergency Day Rules](https://snowdaycalculator.website/florida/): Snow is almost unknown in Florida, so by our rule of thumb half an inch of snow or 0.08 inch of ice would close schools. The State Board can adjust the 180-day rule in an emergency.
- [Georgia Snow Day Calculator: Ice, Rare Snow and Make-Up Days](https://snowdaycalculator.website/georgia/): Snow is rare in Georgia, so half an inch of snow or a thin glaze of ice can close schools, by our rule of thumb. Boards may skip up to 4 make-up days after an emergency.
- [Hawaii Snow Day Calculator: Snow Chances and School-Day Rules](https://snowdaycalculator.website/hawaii/): All 85 of NOAA’s Hawaii stations average no snow, so the calculator’s snow day chance for Honolulu stays near zero. Public schools, except charter and multi-track ones, need 180 days and 1,080 hours.
- [Idaho Snow Day Calculator: Chances, Snow Hours and Virtual Days](https://snowdaycalculator.website/idaho/): By our rule of thumb, about 4.5 inches closes Boise schools about half the time, 7 in Idaho Falls. Boards can take off 11 weather hours; a virtual day can't replace a snow day for attendance funding.
- [Illinois Snow Day Calculator: Chances, Emergency Days and E-Learning](https://snowdaycalculator.website/illinois/): By our rule of thumb, 5 to 6.5 inches closes schools around Chicago. Illinois calendars hold at least five emergency days, and up to five can be e-learning days instead.
- [Indiana Snow Day Calculator: Chances, Make-Up Days and Virtual Days](https://snowdaycalculator.website/indiana/): By our rule of thumb, 2.5 inches closes Evansville schools and 8.5 South Bend’s. Indiana requires 180 days; a virtual day counts if half of it is live, and self-paced ones stop at three.
- [Iowa Snow Day Calculator: Chances, Cold Rules and Make-Up Time](https://snowdaycalculator.website/iowa/): By our rule of thumb, 5 to 6 inches closes schools in Iowa’s biggest cities. Urbandale generally cancels at −25°F or a −30°F wind chill; lost time is made up, and up to five online days count.
- [Kansas Snow Day Calculator: Chances and Forgiven Snow Days](https://snowdaycalculator.website/kansas/): By our rule of thumb, about 3 to 3.5 inches of snow closes Kansas schools about half the time. Districts schedule make-up days, and up to 5 more can be forgiven.
- [Kentucky Snow Day Calculator: Chances, NTI Days and Make-Up Rules](https://snowdaycalculator.website/kentucky/): By our rule of thumb, 2 to 4 inches of snow closes schools in Kentucky's big cities half the time. Missed days are made up, or covered by up to 10 NTI days.
- [Louisiana Snow Day Calculator: Ice, Rare Snow and the 177-Day Rule](https://snowdaycalculator.website/louisiana/): By our rule of thumb, half an inch of snow or about 0.08 inch of ice would close Louisiana schools. Closed days rarely shorten the year: schools still need 63,720 minutes of teaching.
- [Maine Snow Day Calculator: Chances, Make-Up Days and Extended Days](https://snowdaycalculator.website/maine/): By our rule of thumb, 9 to 10.5 inches of snow closes schools in Maine's big cities half the time. Lost days can be made up with one-hour extensions: five equal one day.
- [Maryland Snow Day Calculator: Chances, Virtual Days and Make-Up Rules](https://snowdaycalculator.website/maryland/): By our rule of thumb, 3.5 to 5.5 inches of snow closes schools in Maryland's big cities half the time. Virtual days are allowed only after a calendar's snow days run out.
- [Massachusetts Snow Day Calculator: Chances and the 185-Day Calendar](https://snowdaycalculator.website/massachusetts/): By our rule of thumb, 7.5 to 9 inches of snow closes schools in the big cities of Massachusetts half the time. Districts schedule 185 days but must hold only 180.
- [Michigan Snow Day Calculator: Chances, Forgiven Days and Virtual Days](https://snowdaycalculator.website/michigan/): By our rule of thumb, about 6 inches closes Detroit schools and 10.5 Grand Rapids’. Michigan forgives 6 days, 3 more with a waiver, and from 2026–27 allows up to 3 virtual days.
- [Minnesota Snow Day Calculator: Cold Closings, Snow and E-Learning](https://snowdaycalculator.website/minnesota/): Saint Paul may cancel school when 6 a.m. wind chills are forecast at −35°F or colder. By our rule of thumb, about 8 inches closes Twin Cities schools, and up to five e-learning days count as school.
- [Mississippi Snow Day Calculator: Ice, Rare Snow and the 180 Days](https://snowdaycalculator.website/mississippi/): By our rule of thumb, half an inch to 1 inch of snow, or about 0.08 inch of ice, would close Mississippi schools. State standards call for 180 teaching days; exceptions need approval.
- [Missouri Snow Day Calculator: Chances, Make-Up Hours and AMI Days](https://snowdaycalculator.website/missouri/): By our rule of thumb, about 3 inches of snow closes schools in Missouri's big cities half the time. Lost hours are made up under a 36-hour rule or covered by AMI days.
- [Montana Snow Day Calculator: Chances, Cold and Make-Up Hours](https://snowdaycalculator.website/montana/): Montana schools close for a big storm or deep cold: about 6.5 to 11 inches of snow by our rule of thumb. State law gives each district 1 emergency day a year with nothing to make up.
- [Nebraska Snow Day Calculator: Chances, Snow Totals and School Hours](https://snowdaycalculator.website/nebraska/): By our rule of thumb, about 5 to 5.5 inches of snow closes schools in Omaha and Lincoln about half the time. Nebraska counts school hours and sets no number of snow days.
- [Nevada Snow Day Calculator: Reno Snow and 3 Contingent Days](https://snowdaycalculator.website/nevada/): Reno gets real snow and Las Vegas almost none. By our rule of thumb it takes about 5 inches to close schools in Reno and half an inch in Las Vegas, and every district schedules at least 3 spare days.
- [New Hampshire Snow Day Calculator: Chances, Make-Up Hours, Remote Days](https://snowdaycalculator.website/new-hampshire/): By our rule of thumb, 8 to 9.5 inches of snow closes schools in New Hampshire's big cities half the time. Remote learning can count when weather makes buses unsafe.
- [New Jersey Snow Day Calculator: Chances, 180 Days and Remote Rules](https://snowdaycalculator.website/new-jersey/): By our rule of thumb, 5 to 5.5 inches of snow closes schools in New Jersey's big cities half the time. Remote days count only in longer, declared emergencies.
- [New Mexico Snow Day Calculator: Chances, Make-Up and Remote Days](https://snowdaycalculator.website/new-mexico/): By our rule of thumb, New Mexico schools close at about half an inch to 4.5 inches of snow, depending on the city. Lost time must be made up, and up to 4 days a year can be taught remotely.
- [New York Snow Day Calculator: Chances, Lake Snow and Remote Days](https://snowdaycalculator.website/new-york/): By our rule of thumb, about 5 inches closes schools in New York City and 14.5 in Syracuse. Only districts decide; the state allows remote days and can forgive up to five weather days.
- [North Carolina Snow Day Calculator: Chances, Make-Up and Remote Days](https://snowdaycalculator.website/north-carolina/): In most of North Carolina, 1 to 2 inches of snow or a thin glaze of ice can close schools, by our rule of thumb. Every calendar must plan how weather days are made up.
- [North Dakota Snow Day Calculator: Chances, Cold and Virtual Days](https://snowdaycalculator.website/north-dakota/): By our rule of thumb, 7 to 8 inches of snow closes North Dakota schools about half the time, and cold near −40°F can too. Only lost hours are made up, and virtual days can count.
- [Ohio Snow Day Calculator: Chances, Hours Rule and No Calamity Days](https://snowdaycalculator.website/ohio/): By our rule of thumb, about 4 inches closes schools in Cincinnati and Dayton, 9.5 in Cleveland. Ohio counts hours, not days: no calamity days, and only hours below the minimum are made up.
- [Oklahoma Snow Day Calculator: Ice, Snow and 2026–27 Virtual Days](https://snowdaycalculator.website/oklahoma/): By our rule of thumb, half an inch to 2 inches of snow or about a tenth of an inch of ice closes Oklahoma schools. From 2026–27, closed days taught online count only in narrow cases.
- [Oregon Snow Day Calculator: Chances and the New 16-Hour Rule](https://snowdaycalculator.website/oregon/): By our rule of thumb, 1 to 1.5 inches of snow closes schools in Portland, Salem and Eugene about half the time. Since October 16, 2026, up to 16 hours lost to bad weather can count.
- [Pennsylvania Snow Day Calculator: Chances, Make-Up Days and FIDs](https://snowdaycalculator.website/pennsylvania/): By our rule of thumb, about 4 inches closes Philadelphia schools and 13.5 Erie’s. Schools need 180 days or set hours, and may use up to five Flexible Instructional Days.
- [Rhode Island Snow Day Calculator: Chances, Make-Up and Virtual Days](https://snowdaycalculator.website/rhode-island/): By our rule of thumb, about 6 to 7 inches of snow closes Rhode Island schools about half the time. Calendars carry 4 make-up days, and up to 5 virtual days need approval first.
- [South Carolina Snow Day Calculator: Make-Up Days and eLearning](https://snowdaycalculator.website/south-carolina/): By our rule of thumb, half an inch to 1 inch of snow, or about 0.08 inch of ice, closes South Carolina schools. Missed days must be made up; approved districts can use 5 eLearning days.
- [South Dakota Snow Day Calculator: Chances, Cold and School Hours](https://snowdaycalculator.website/south-dakota/): By our rule of thumb, about 6 to 7.5 inches of snow closes South Dakota schools about half the time. Schools count hours, and once they have them, weather days need no make-up.
- [Tennessee Snow Day Calculator: Chances and Stockpile Days](https://snowdaycalculator.website/tennessee/): Half an inch to 1.5 inches of snow or a thin glaze of ice can close Tennessee schools, by our rule of thumb. Districts can bank up to 13 stockpile days to cover weather closings.
- [Texas Snow Day Calculator: Ice, Snow and the New Make-Up Days](https://snowdaycalculator.website/texas/): In most of Texas, half an inch of snow or a thin glaze of ice can close schools, by our rule of thumb. From 2026–27, district calendars must carry two make-up days.
- [Utah Snow Day Calculator: Chances, Contingency Days and Waivers](https://snowdaycalculator.website/utah/): By our rule of thumb, 7 to 9 inches of snow closes schools in Salt Lake City, Provo and Orem about half the time, and half an inch in St. George. Calendars must hold contingency days.
- [Vermont Snow Day Calculator: Chances, Waivers and the 175-Day Rule](https://snowdaycalculator.website/vermont/): By our rule of thumb, 10.5 to 12 inches of snow closes schools in Vermont's biggest towns half the time. Schools need 175 days, and the State Board can waive lost ones.
- [Virginia Snow Day Calculator: Chances, Remote Days and Make-Up Rules](https://snowdaycalculator.website/virginia/): By our rule of thumb, 1 to 3 inches of snow closes schools in Virginia's big cities half the time. Missed days are made up by formula, or replaced by up to 10 remote days.
- [Washington Snow Day Calculator: Hills, Snow and Make-Up Days](https://snowdaycalculator.website/washington/): By our rule of thumb, 1 to 2 inches of snow closes schools around Seattle about half the time, and about 7 inches in Spokane. Lost days are made up, through June 14 if need be.
- [West Virginia Snow Day Calculator: Chances, NTI and Make-Up Days](https://snowdaycalculator.website/west-virginia/): By our rule of thumb, 3 to 5 inches of snow closes West Virginia schools about half the time. Lost days are made up, up to 5 NTI days can count, and hours replace days in 2027.
- [Wisconsin Snow Day Calculator: Chances, Cold Rules and Make-Up Hours](https://snowdaycalculator.website/wisconsin/): By our rule of thumb, 6.5 to 8.5 inches closes schools in Wisconsin’s biggest cities. Districts set their own cold rules, and hours lost to a closing must be made up unless taught online.
- [Wyoming Snow Day Calculator: Chances, Cold and the 175-Day Rule](https://snowdaycalculator.website/wyoming/): Wyoming schools close for a big storm or bitter cold: about 6.5 to 10 inches of snow by our rule of thumb. A closed day must be made up if it leaves a school under 175 days.

## Data files (CSV)

- [Snow day chances for the next school day in 296 U.S. cities](https://snowdaycalculator.website/snow-day-chances-by-city.csv): updated every half hour.
- [How much snow closes school in 296 U.S. cities](https://snowdaycalculator.website/snow-day-closing-points-by-city.csv).
- Normal snowfall by station, one file a state, such as [Michigan](https://snowdaycalculator.website/normal-snowfall-michigan.csv).

## About

- [How the Snow Day Calculator Works: Every Rule, With Its Data](https://snowdaycalculator.website/how-it-works/): Every rule the calculator works by, with the data behind it
- [About Snow Day Calculator](https://snowdaycalculator.website/about/): Who publishes the site, and who pays for it
- [Corrections](https://snowdaycalculator.website/corrections/): How to report a mistake

## Full text

- [Every page of the site as text](https://snowdaycalculator.website/llms-full.txt)