Delaware Snow Day Calculator: Chances, Delays and School Hours

Delaware’s snow comes in modest amounts, and more of it falls around Wilmington and Newark than around Dover and Milford. Wilmington’s normal is 19.4 inches a year and Newark’s 19.5, while Dover’s is 13.3 and Milford’s 12.9, by NOAA’s 1991–2020 normals. By our rule of thumb, about 4 inches of overnight snow gives Wilmington, Newark or Middletown schools an even chance of closing, and about 3 inches in Dover or Milford.

Delaware counts school in hours. State law sets 1,060 hours a year for kindergarten through grade 11 and 1,032 for grade 12. Local boards decide which days to close for storms, and the hours “may be adjusted accordingly,” but excusing a district from the hour requirement takes the approval of the Secretary of Education and the State Board of Education. A weather delay can last no more than two hours.

How much snow closes school in Delaware?

About 3 to 4 inches, by our rule of thumb. That is the overnight snow at which schools close about half the time, worked out from each city’s normal snowfall, so it is a middle point, not a line.

Delaware'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.

The cities split into three groups. Wilmington (19.4 inches a year), Newark (19.5) and Middletown (18.1) sit near 4 inches; Smyrna (15) is near 3.5; Dover (13.3) and Milford (12.9) near 3. The cold points split in two: −18°F in Wilmington, Newark and Middletown, and −16°F in Dover, Milford and Smyrna.

Timing is the other half. The calculator counts snow fully when it falls overnight (9 PM to 6 AM) or while buses run (6 to 10 AM), at 80% in the afternoon and evening before, 45% during the school day and 35% the morning before. Snow that falls while it is above freezing counts less, since it tends to leave roads wet. More on how the calculator works.

Ice counts on its own. By the calculator’s rule, about a tenth of an inch of ice closes schools almost anywhere, while the National Weather Service usually issues an Ice Storm Warning at about a quarter inch or more. Weather Service warnings add to the calculator’s chance, and watches and advisories add less.

Where does Delaware get the most snow?

Around Wilmington. NOAA keeps snowfall normals for just five Delaware weather stations, and the Wilmington New Castle County airport station leads at 20.2 inches a year. Dover follows at 13.2, Greenwood at 12.8, a second Wilmington station (Porter Research) at 12.0, and Lewes, about 10 feet above sea level, at 10.5.

Normal snowfall a year and normal December to February low at each of the 5 weather stations in Delaware 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.

Every station in Delaware, snowiest first

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

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

With five stations, the snowiest and least snowy lists are the same places in a different order. Half average 12.8 inches or less. The two Wilmington stations differ by about 8 inches a year, a reminder that one station’s normal is not your street’s, which is why the calculator reads the forecast for the middle of your own ZIP code.

Do snow days have to be made up in Delaware?

Not automatically. Delaware counts hours, and after storms the hours can be adjusted, with state approval. The law, 14 Del. C. §1049, sets 1,060 hours a year for kindergarten and grades 1–11 and 1,032 for grade 12, a table in force since the 2008–09 school year.

The storm rule is in 14 Del. C. §122(b)(9). The local board decides which days schools close for storms, staff keep their pay, and the hour total may be adjusted. But “any excusal of educational hour requirements” must be approved by the Secretary of Education and the State Board of Education. The law sets no fixed number of forgiven days.

We did not find Department of Education guidance on how the State Board handles those requests, so we cannot say how often it says yes. Your district’s calendar shows how many hours it schedules above the minimum. We read the code as it stood on October 1, 2026.

How long can a weather delay be in Delaware?

Two hours at most. Delaware law says a weather delay or early dismissal “shall be no more than 2 hours,” and a school day must still be at least 3.5 hours long, not counting lunch, under the state code.

That shapes what a snowy morning can bring. The calculator’s three results are a snow day, a late start and school as usual, and in Delaware a late start means a delay of up to two hours. Because the law caps a delay at two hours, a district cannot answer a slow-clearing storm with a longer one. The same limit covers early dismissals for weather.

Can Delaware schools switch to remote learning instead?

Delaware’s school code, as we read it, does not say. We searched all of Title 14 of the Delaware Code, as it stood on October 1, 2026, and found no provision for remote or virtual days during a weather closing, and we did not find Department of Education guidance on them.

If your district offers remote days, its own policy is the place to read how they count toward the hours.

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

Far colder than a normal winter morning, by our rule of thumb: a wind chill near −16°F at bus time in Dover, Milford and Smyrna, and −18°F in Wilmington, Newark and Middletown. That is each city’s normal December–February low minus 45°F. We have no Delaware district’s own cold number on file.

The calculator reads the wind chill from 5 to 9 AM and adds to its chance when the National Weather Service issues cold alerts. The top one is now the Extreme Cold Warning, for “extremely dangerous cold conditions or wind chill values”; it replaced the Wind Chill Warning on or about October 1, 2024. The Weather Service’s wind chill chart shows that at 0°F with a 15 mph wind, the wind chill is −19°F and exposed skin can freeze in 30 minutes.

Who decides, and when do Delaware families hear?

Your local school board. Under 14 Del. C. §122(b)(9), the local board decides which days schools close for storms. Boards also adopt their calendars by April 30 for the following school year, and may amend them only after 30 days’ public notice, under the state code.

We have not found a Delaware district’s announcement clock, so check your district’s website, app or local TV and radio for the final word. The calculator reads the Weather Service forecast from 6 AM the day before to 3 PM on the school day, so its chance can change as a storm gets closer.

It is independent: not a school district, the Department of Education or the National Weather Service. It shows the reasons behind each chance so you can judge them.

The page at a glance:

Snow days in Delaware

• What closes schools
  • 4 inches around Wilmington
  • 3 inches in Dover
  • a tenth of an inch of ice
• School hours
  • 1,060 hours K to 11
  • 1,032 hours grade 12
  • a 3.5-hour minimum day
• After storms
  • hours may be adjusted
  • excusal needs state approval
• Delays
  • 2 hours at most
  • the same limit for early dismissals
• Remote days
  • not in the state code we read
  • check district policy

Questions people ask

How long can a school delay be in Delaware?

Two hours. The state code caps a weather delay or early dismissal at two hours.

Do Delaware schools make up snow days?

Delaware counts hours, not days. After storms the hours may be adjusted, but excusing a district from the hour requirement takes the approval of the Secretary of Education and the State Board, under §122(b)(9). A district with hours to spare may not need to add any time.

Does Delaware allow virtual snow days?

Not in the state code we read: Title 14 has no provision for remote days during a weather closing. Ask your district what its own policy says.

How much snow does it take to close school in Wilmington?

About 4 inches overnight, by our rule of thumb: the amount at which Wilmington schools close about half the time. Ice, timing and wind can change that, and your district decides.

Sources: Delaware Code, Title 14 (as of October 1, 2026); 14 Del. C. §1049; 14 Del. C. §122.

Facts checked October 29, 2026.

Updated October 29, 2026