California Snow Day Calculator: Sierra Snow and the J-13A Form

Snow days in California are a mountain thing. Los Angeles, San Diego, San Francisco, Fresno and Sacramento all have a snowfall normal of 0 inches, so by our rule of thumb even half an inch overnight would close schools there about half the time. The snow is up high: the snowiest NOAA station in the state, Soda Springs, averages 445 inches a year.

Type your ZIP code above to see the chance for your school. The calculator reads the National Weather Service forecast for your own spot and blends the NOAA stations nearest it, so a school in the mountains is judged by mountain snow.

When snow does close schools, California law names it. A district kept from holding its 180 days “because of fire, flood, earthquake, snowstorm, or epidemic” can keep its funding (Education Code 41422), and the way to ask is Form J-13A, sent to the California Department of Education.

How much snow closes school in California?

In the 6 biggest cities, about half an inch by our rule of thumb, the lowest it goes. The calculator’s closing point grows with a place’s normal snowfall, and these cities have little or none.

California's six largest cities: normal snowfall a year (NOAA 1991–2020) and the snowfall and wind chill at which, by our rule of thumb, schools there usually close.

Our rule of thumb: the usual closing point is 0.5 × (normal snowfall a year)^0.7, the cold point the normal December–February low minus 45°F. How the calculator works.

All six have a snowfall normal of 0. Near San Jose, Mt. Hamilton, about 4,200 feet up, gets 18.1 inches a year, but the calculator counts a station far above a city for little, so San Jose’s normal comes from the valley stations around it, which show 0.

In the mountains the closing point climbs with the snow. Our rule of thumb tops out at 15 inches, which it reaches for any place that averages about 130 inches a year or more, and several mountain stations average far more. Where snow is rare, ice counts too: by our rule, about 0.08 inch of ice closes schools there.

Where does California get the most snow?

In the mountains, such as the Sierra. Of NOAA’s 278 California stations with a snowfall normal for 1991–2020, the snowiest is Soda Springs, at about 6,890 feet, with 445 inches a year. Lodgepole (220.4 inches), Truckee (206.6), Grant Grove (186.0), Donner Memorial State Park (182.9) and Tahoe City (179.0) follow, and Chester (109.6) and Canyon Dam (109.3) also top 100 inches.

Normal snowfall a year and normal December to February low at each of the 278 weather stations in California with a snowfall normal in NOAA's U.S. Climate Normals for 1991–2020, with each station's location, elevation and how complete its record is.

The 10 snowiest and 5 least snowy of 278 stations in California

Download “Normal snowfall at California weather stations, 1991–2020” (CSV, opens in Excel)

Built from: U.S. Climate Normals, 1991–2020 (National Centers for Environmental Information).

The middle of the list is 0.0 inches: 168 of the 278 stations average no snow at all. That is why the calculator works from the stations nearest each ZIP code rather than one number for the state.

Do snow days have to be made up in California?

Not if the state approves a J-13A request. California’s emergency-closure law counts a full year as at least 180 days for a school district or county office of education and 175 for a charter school (Education Code 41422, as amended effective January 1, 2025). Districts must also offer yearly minutes: 36,000 for kindergarten, 50,400 for grades 1 to 3, 54,000 for grades 4 to 8 and 64,800 for grades 9 to 12 (Education Code 46207).

When an emergency such as a snowstorm keeps a school from meeting those, the district files Form J-13A. Approval gives it the authority to hold school for fewer days and minutes without a funding penalty (J-13A quick guide, 2026). The school board approves the request, the county office of education signs it, and the county sends it to the Department of Education (J-13A quick guide; J-13A FAQ).

There is no deadline for filing, and the department asks districts to use any built-in make-up days, or add time to the calendar, first where they can (J-13A quick guide, 2026). Approval does not depend on that, its J-13A FAQ says. No number of weather days is free by law; the department decides each request.

Can California schools switch to remote learning instead?

Not to keep the funding. The department’s 2026 quick guide says independent study “cannot be used to generate attendance” during an emergency school closure (J-13A quick guide).

Schools still have to keep teaching. For closures from July 1, 2026, the J-13A rules also require a board-adopted school safety plan with an instructional continuity plan: two-way communication within 5 days and instruction within 10 instructional days. The district must certify that it carried out the plan, or explain why not (Education Code 46393, as amended by AB 176 of 2024). Districts must still offer independent study in line with that plan (J-13A quick guide).

How cold does it have to be to close school in California?

We found no state cold rule and no California district’s cold number in our research. In the big cities, our rule of thumb sets cold points from 0°F in Los Angeles, San Diego and San Francisco to −5°F in Fresno and Sacramento, since their normal winter lows run from 40°F to 50.3°F. San Jose’s is −3°F.

The alert to watch is the National Weather Service’s Extreme Cold Warning, which means extremely dangerous cold or wind chills are expected or occurring (NWS cold alerts). Each local Weather Service office sets its own thresholds (NWS wind chill chart), and the calculator raises the chance when a warning is out for your area.

Who decides, and when do families hear?

Your district decides. In the Department of Education’s words: “It is a local decision whether a school should close due to an emergency” (J-13A quick guide, 2026).

Charter schools file their own J-13A requests, and the county superintendent signs every one (J-13A FAQ). We did not find a California district’s closing clock in our research, so check your district’s website, app or local news. The calculator reads snow from 6 a.m. the day before to 3 p.m. on the school day, so look the evening before and again early in the morning.

Snow days in California

• Big cities
  • Snowfall normal 0 inches
  • Half-inch closing point
• Mountains
  • Soda Springs 445 inches
  • Rule tops out at 15 inches
• School year
  • 180 days, 175 for charters
  • Minutes by grade
• Closed days
  • Form J-13A
  • Board, county, then state
• Remote teaching
  • Not counted for funding
  • Continuity plan from July 2026

Questions people ask

What is a J-13A form?

It is California’s Request for Allowance of Attendance Due to Emergency Conditions. A district files it after an emergency such as a snowstorm, and the Department of Education’s approval lets it hold school for fewer days and minutes without a funding penalty (Form J-13A page).

Does California make up snow days?

Not always. A district can ask the state to approve the lost days on Form J-13A instead. The department asks districts to use built-in make-up days first where they can, but approval does not depend on it (J-13A FAQ).

Why doesn’t Mt. Hamilton’s snow count for San Jose?

Because it stands about 4,200 feet up, far above the city. The calculator weighs the NOAA stations nearest a place, and a station much higher or lower than the nearest one counts for little. So San Jose’s normal is the valley stations’ 0, not Mt. Hamilton’s 18.1 inches a year, and its closing point is half an inch, by our rule of thumb.

Do California schools go remote on a snow day?

Independent study does not earn attendance funding during an emergency closure (J-13A quick guide). But from July 1, 2026, districts must have a plan to keep teaching, and must certify they carried it out or explain why not (Education Code 46393). Your district decides what a closed day looks like.

Sources: Education Code 41422 (emergency closures), California Department of Education, J-13A FAQ and J-13A quick guide (2026).

Facts checked October 29, 2026.

Updated October 29, 2026