Snow Day Calculator
Will school be closed tomorrow?
Enter your ZIP code, town or school district to see the chance of a snow day tomorrow, based on tonight's National Weather Service forecast.
Loading tonight's forecast…
Snow by hour
From the National Weather Service forecast, updated hourly. Estimate only. Your district makes the call.
Snow day chances across the U.S.
- 0–29%Unlikely
- 30–59%Possible
- 60–79%Likely
- 80–95%Very likely
- No forecast (Alaska, Hawaii) or no school
Highest chances tonight
| State | Highest closure chance |
|---|---|
| Loading tonight's forecast… | |
Highest chance among each state's ZIP codes, as of tonight. All states
How this snow day calculator works
- 1.
Tonight's forecast
Snow, ice and wind chill for your ZIP from the National Weather Service, for the hours that decide a snow day: 6 PM to 8 AM.
- 2.
Your local normal
NOAA climate normals for your area. An inch in Atlanta counts for much more than an inch in Buffalo.
- 3.
Alerts and timing
Winter storm, ice storm and extreme cold warnings raise the chance. Snow at bus time counts the most.
- 4.
Your district's chance
Closure and delay chances, updated every hour overnight, for your school district.
Full method and sources · 5-day snow day predictor · Cold day calculator · Manual calculator: test your own storm · College snow day calculator
What the percentages mean
| Color | Chance | Meaning |
|---|---|---|
| 0–29% | Unlikely | |
| 30–59% | Possible | |
| 60–79% | Likely | |
| 80–95% | Very likely |
Chances are capped at 95%: only your district can make it certain.
What closes schools
- Snow
- How much falls overnight, compared with what your area handles every winter.
- Ice
- Even a tenth of an inch of freezing rain can close roads. Ice counts more than snow.
- Wind chill
- Dangerous cold at the bus stop closes schools with no snow at all. Cold day calculator.
- Timing
- Snow at 6 AM matters more than snow at 9 PM that crews can clear.
How much snow usually closes schools
| City | Snow a year | Days with 3+ in. | Snow that usually closes schools |
|---|---|---|---|
| Atlanta, GA | 1 in. | 0.0 | about 1 in. |
| Nashville, TN | 3 in. | 0.1 | about 2 in. |
| Washington, DC | 10 in. | 1.3 | about 5 in. |
| New York, NY | 25 in. | 3.0 | about 7 in. |
| Chicago, IL | 39 in. | 3.6 | about 7 in. |
| Denver, CO | 49 in. | 4.7 | about 8 in. |
| Minneapolis, MN | 51 in. | 5.0 | about 8 in. |
| Buffalo, NY | 95 in. | 9.1 | about 11 in. |
NOAA NCEI 1991–2020 climate normals. Last column: our model's closing line for overnight snow, not a district policy. How much snow cancels school.
How many inches for a snow day, by place
There is no national number. We sorted the 99 cities we forecast by the overnight snow that usually closes schools there, using NOAA climate normals. The snowier a place is every winter, the more snow it takes.
- 3–5 inches · 19 cities
- Charlotte, Seattle, Oklahoma City, Washington, Louisville, Portland
- 6–8 inches · 50 cities
- New York, Chicago, Philadelphia, Columbus, Indianapolis, Denver
- 9 inches or more · 24 cities
- Cleveland, Buffalo, Salt Lake City, Worcester, Rochester, Grand Rapids
Our model's closing line for snow falling 6 PM–8 AM. Your district may close sooner or later.
Ice and extreme cold
Ice closes schools almost everywhere, because buses can't stop on it. A tenth to a fifth of an inch of freezing rain on untreated roads is enough in many places, and the line barely moves with climate:
| City | Ice that usually closes schools |
|---|---|
| Atlanta, GA | .12 in. |
| Washington, DC | .15 in. |
| Chicago, IL | .18 in. |
| Buffalo, NY | .21 in. |
Cold works the other way: districts used to cold mornings wait for far colder wind chills. The line comes from each place's normal winter low:
| City | Normal winter low | Wind chill that closes schools |
|---|---|---|
| Minneapolis, MN | 12°F | −33°F |
| Chicago, IL | 23°F | −22°F |
| Buffalo, NY | 21°F | −24°F |
| Denver, CO | 18°F | −27°F |
| New York, NY | 30°F | −20°F |
| Atlanta, GA | 35°F | −20°F |
Wind chill at bus time (5–8 AM). Cold day calculator.
When to check, and when districts decide
The evening before is when most families plan. From mid-October to mid-April the calculator refreshes every hour from 2 PM to 9 AM Eastern, as the National Weather Service updates its forecast. A chance that holds steady from 8 PM to bedtime is worth planning around.
Early morning is when most districts decide. Staff drive the roads and check the latest forecast in the small hours, and the decision goes out before the first buses. Before 9 AM local time the calculator showstoday and keeps updating, so a 5:30 AM check shows the storm as it is.
The night before is common when a big storm is certain, so families can arrange childcare. Some districts announce a delay first and upgrade it to a closure once crews have seen the roads. What time snow days are announced.
A chance of snow is not a chance of a snow day
A weather app's "60% chance of snow" means it may snow at all, maybe a dusting in the afternoon. That says little about school. A district asks narrower questions: how much falls overnight, is it still falling at bus time, is there ice under it, and how cold is it at the bus stop.
So the calculator doesn't use the chance of snow. It reads the forecast amounts of snow and ice hour by hour from 6 PM to 8 AM, the wind chill from 5 to 8 AM, and any winter storm, ice storm, blizzard or extreme cold warning for your county. Snow that falls after 8 AM counts less, because it leads to early dismissals more than closures.
Then it compares those amounts with your area's normal winter. Three inches overnight is a snow day in Atlanta and an ordinary morning in Buffalo.
How we check our accuracy
Many snow day calculators call themselves accurate or quote a percentage. We won't publish a number until we can show where it came from. After each storm night, parents and students tell us what their district did (closed, delayed, early dismissal or open), and we compare that with the chance we showed the evening before.
A well-calibrated calculator should see schools close on about 8 of every 10 nights it calls "very likely", and on about 2 of 10 it calls "unlikely". We will publish those numbers on the accuracy page this winter, misses included. Report your district's decision to help.
What the calculator can't know
- Your district's own habits: some close at the first sign of ice, some almost never close.
- Road crews, power outages, staff shortages and building problems such as frozen pipes.
- How many snow days your district has used, which can make it slower to call another. You can set this under "Adjust for your school" on the result.
- A storm that shifts 30 miles overnight. Forecasts change, and so does the chance.
That is why every chance stops at 95%. To test a storm yourself, try the manual snow day calculator.
How to find out if school is canceled
The calculator gives you the odds; only your district gives you the answer. The official decision comes through the district's own channels, usually in this order:
- Text, phone or email alert from the district's notification system. Make sure your contact details are current in the school's parent portal: it is the fastest way to hear.
- The district website, usually as a banner on the home page, and its social media accounts.
- Local TV and radio closing lists, which pick up the district's announcement within minutes.
Each district page on this site links to the district's official website. If a closure is announced, believe the district, not us: we never report official closings.
Planning for a possible snow day
- Check twice. Once in the evening, when most families plan, and once early in the morning, when the forecast is freshest and most districts decide.
- Watch the delay chance too. A high delay chance with a low closure chance usually means a late start: plan for a later bus, not a day at home.
- Look at the hours, not just the total. The "snow by hour" chart on the result shows whether the heaviest snow lands before buses run or after.
- Have a childcare plan when the chance is above 60%. "Likely" nights turn into closures more often than not.
- Add the calculator to your home screen from the App page, so the 5:30 AM check takes one tap.
Snow day vs. delay vs. early dismissal
Snow day
No school all day. Usually heavy snow or ice still falling at bus time, or extreme cold.
Delay
School starts later, often 2 hours, so crews and daylight can clear the roads.
Early dismissal
School ends early because a storm arrives during the day.
Popular places
- Anchorage, AK
- Aurora, CO
- Boston, MA
- Buffalo, NY
- Chicago, IL
- Cleveland, OH
- Colorado Springs, CO
- Columbus, OH
- Denver, CO
- Detroit, MI
- Grand Rapids, MI
- Indianapolis, IN
- Madison, WI
- Milwaukee, WI
- Minneapolis, MN
- New York, NY
- Philadelphia, PA
- Rochester, NY
- Salt Lake City, UT
- Syracuse, NY
School districts
- Ann Arbor Public Schools
- Boston Public Schools
- Buffalo Public Schools
- Charlotte-Mecklenburg Schools
- Chicago Public Schools
- Cincinnati Public Schools
- Cleveland Metropolitan School District
- Columbus City Schools
- Denver Public Schools
- Des Moines Public Schools
- Detroit Public Schools
- Fairfax County Public Schools
- Grand Rapids Public Schools
- Indianapolis Public Schools
- Jeffco Public Schools
States
Alabama · Alaska · Arizona · Arkansas · California · Colorado · Connecticut · Delaware · District of Columbia · Florida · Georgia · Hawaii · Idaho · Illinois · Indiana · Iowa · Kansas · Kentucky · Louisiana · Maine · Maryland · Massachusetts · Michigan · Minnesota · Mississippi · Missouri · Montana · Nebraska · Nevada · New Hampshire · New Jersey · New Mexico · New York · North Carolina · North Dakota · Ohio · Oklahoma · Oregon · Pennsylvania · Rhode Island · South Carolina · South Dakota · Tennessee · Texas · Utah · Vermont · Virginia · Washington · West Virginia · Wisconsin · Wyoming
Guides
How many snow days are schools allowed?
Forgiven days, waivers, make-up rules and remote days in the 12 snowiest states, from each state's law.
How much snow cancels school?
From one inch in Atlanta to a foot in Buffalo: what it takes in every state, with NOAA data.
How school districts decide snow days
Who makes the call, what they check before dawn, and why neighboring districts disagree.
Snow day vs. delay vs. early dismissal
What each one means, when districts use them, and how the calculator scores each.
Ice storms and school closings
Why a tenth of an inch of ice can close more schools than a foot of snow.
What time are snow days announced?
When districts decide, how they tell families, and when to check the calculator.
Virtual snow days: is a remote day the new snow day?
How remote learning days work, why districts use them, and what they mean for families.
Signs of a snow day tomorrow
The forecast signs that really matter, and the folklore that doesn't.
Snow day checklist for parents
What to set up the night before a possible snow day, and what to do in the morning.
Snow day calculators: how they work and why they exist
From guessing games to forecast data: what a snow day calculator can and can't know.
Winter Storm Warning vs. Watch vs. Advisory
Every NWS winter alert in plain words, what replaced the Heavy Snow Warning, and what each means for school.
What is a snow squall?
Sudden whiteouts, flash freezes and the Snow Squall Warning, and how a squall differs from a blizzard.
Lake-effect snow and school closings
Why one Great Lakes town gets a foot and the next gets flurries, and how much it takes to close snowbelt schools.
Ohio snow emergency levels and school closings
What Level 1, 2 and 3 mean, who declares them, and why a snow emergency doesn't by itself close schools.
Wind chill and school closings
How cold is too cold for school, the NWS cold alerts, and local cold lines by city.
Snow day calculator questions
How does the snow day calculator work?
Every hour it reads the National Weather Service forecast for your ZIP code (snow and ice between 6 PM and 8 AM, wind chill at bus time, active warnings), compares it with your area's normal winter from NOAA climate data, and turns that into a chance of a closure and of a delay.
Is 2 inches of snow enough for a snow day?
Where snow is rare, often yes. In snowy regions, usually not: 2 inches is a normal winter morning there. That is why the calculator compares the forecast with your local normal.
When does the calculator update?
Every hour from 2 PM to 9 AM Eastern, mid-October to mid-April. Before 9 AM local time it shows today; after that, the next school day.
How accurate is it?
We don't publish an accuracy number yet. We will measure it against parent reports this winter and publish the results, including where we miss.
Why is the chance capped at 95%?
Only your district can announce a closure. Districts sometimes stay open in heavy snow and sometimes close for reasons no forecast shows.
Does it work for my school district?
It covers about 13,000 public school districts and 33,600 ZIP codes in the U.S. If several districts serve your ZIP, pick yours from the list. Many private schools follow the local public district.
What is the difference between a snow day and a delay?
A snow day closes school for the day; a delay opens it later so crews can clear roads. The calculator shows both. The delay chance includes closures, so it is never lower.
Is it free?
Yes. No account, no app store: you can add it to your home screen from the App page.
Is the snow day calculator real?
It is a real forecast tool, not a joke or a random number. It uses the National Weather Service forecast for your ZIP code and NOAA climate records for your area. But it is an estimate: it cannot know what your superintendent will decide, so treat it like a weather forecast, not an announcement.
How many inches of snow do you need for a snow day?
It depends on where you live. Using NOAA normals, our model's closing line is about 1 in. of overnight snow in Atlanta, about 7 in. in New York City and about 11 in. in Buffalo. Ice, timing and wind chill can close schools with much less snow.
What is the trick for getting a snow day?
There isn't one. Pajamas inside out and spoons under the pillow are fun traditions, but snow days come from snow or ice at bus time, extreme cold and the roads. The best you can do is check the forecast the night before and again early in the morning.
Which states get the most snow?
By typical yearly snowfall across their ZIP codes (NOAA 1991–2020 normals), the snowiest states in the lower 48 are Vermont, Maine, New Hampshire, New York, Wyoming. Snowy states also need the most snow to close: surprise closures are more common where snow is rare.
Data and honesty
Forecasts and alerts: National Weather Service. Snowfall normals: NOAA National Centers for Environmental Information. School districts: National Center for Education Statistics. Every chance is an estimate; your district makes the call. Independent; not affiliated with the National Weather Service or any school district.