US ZIP (e.g. 10001), Canadian postal code (e.g. M5V 3L9), or a city name.
That's the question this snow day calculator is built to answer. Instead of doom-scrolling the district Facebook page at 11 p.m. or refreshing the same three weather apps until your battery dies, you type in a ZIP code, Canadian postal code, or city name and get a single, clear snow day probability — a percentage chance that your school closes, delays, or goes remote because of snow, ice, or dangerous cold.
Under the hood, this is a live snow day predictor, not a static guess. Every time you calculate, the tool pulls tomorrow's actual forecast — snowfall total, overnight low temperature, wind speed, and precipitation type — straight from Open-Meteo, a meteorological data provider used by researchers, airlines, and weather apps around the world. That live forecast is then run through the same kind of scoring logic a superintendent uses at 5 a.m. before making the call: how much snow, how cold, how windy, and how icy the roads will be for buses and walkers.
Because it's calculating your specific coordinates rather than a regional average, the result you see is tailored to your town, not the nearest big city an hour away. A 70% chance of a snow day in Buffalo means something very different than a 70% chance in Atlanta, and this school snow day calculator takes that local context into account with every forecast it pulls.
No snow day calculator — this one included — can replace the actual phone call a superintendent makes at 5 a.m. Closure decisions also weigh things a weather API can't see: how many buses a district has, whether roads were pre-treated, teacher commute distances, and even how the last storm played out. So think of this tool as a probability, not a promise.
That said, the calculator is only as accurate as the forecast feeding it, which is why it always pulls the latest available data rather than a stale forecast from earlier in the day. Predictions naturally sharpen as the storm gets closer — a forecast run 48 hours out will move around more than one run the evening before school. If you're asking "is this snow day calculator accurate," the honest answer is: it's a reliable read on the weather side of the equation, and the closer you check to the actual morning, the more that read lines up with what your district decides.
For the most dependable result, check back the evening before and again first thing in the morning. Overnight snowfall totals and temperature drops can shift a forecast from "unlikely" to "probable" in a matter of hours, so a same-day check is always more accurate than a prediction from three days out.
Type in a US ZIP code, a Canadian postal code (FSA or full format), or a city name. The calculator works for school districts across the US and Canada, and for any city name it can resolve, though snow day predictions matter most where winter weather actually threatens closures.
Your ZIP code, postal code, or city is converted into exact latitude and longitude coordinates using the Open-Meteo geocoding database, which covers millions of populated places. This is what lets the calculator give you a hyper-local result instead of a broad regional guess.
The tool retrieves tomorrow's daily forecast: expected snowfall total, high and low temperature, wind speed, precipitation probability, and the weather code describing tomorrow's dominant condition, whether that's snow, freezing rain, or ice pellets.
Each weather factor adds points to a running score using the snow day calculator formula below. Heavy snowfall carries the most weight, with freezing temperatures, strong wind, and icy conditions adding on top. The total is capped at 100% and shown to you as your snow day chance for tomorrow.
Once the calculator finishes, your result lands in one of five likelihood tiers. Here's what each range of your snow day percentage typically means for tomorrow's schedule:
Districts in snowier climates tend to need a higher score before calling a closure, since roads, sidewalks, and bus fleets are set up to handle routine snow. In areas that rarely see winter weather, even a "Moderate" score can be enough to shut schools down for a day, since there's little equipment on hand to clear roads quickly.
Curious how does a snow day calculator actually work behind the scenes? This one weighs four primary weather variables, mirroring the factors school administrators consider most when deciding whether to call a snow day:
Snowfall total is the single biggest factor in the formula. More than 5 cm of expected snowfall adds 40 points to the score. Between 2 and 5 cm adds 25 points, and any measurable snowfall above 0.5 cm adds 10 points. Total accumulation is consistently the number one thing administrators cite when explaining a closure.
Freezing temperatures add 20 points when the overnight low drops below 0°C (32°F). Even a light dusting of snow becomes a serious hazard once temperatures stay below freezing, because it compacts into ice on roads and sidewalks instead of melting off by morning.
Strong wind adds 10 points once sustained speeds pass 32 km/h (20 mph). Wind drives visibility down through blowing and drifting snow and makes bus routes and walking routes more dangerous, even when the total snowfall on its own looks modest.
Weather code — the code describing tomorrow's dominant condition — adds 20 points for heavy snow or snow showers and 10 points for freezing rain or ice pellets. Ice is arguably the most dangerous condition of all for buses and pedestrians, which is why it can trigger a closure even when total accumulation is fairly low.
Add those points together and you get a score from 0 to 100, capped at 100%, which is exactly the snow day percentage you see on screen after you hit Calculate.
You can run this calculator with a five-digit US ZIP code, a Canadian postal code in FSA or full format (like M5V or M5V 3L9), or simply a city name if you don't have a ZIP handy. Each format is geocoded to precise coordinates before the forecast is pulled, so a search for a small town gets its own local weather instead of borrowing data from a bigger city nearby.
This also makes the tool useful well beyond K-12 families. College students checking whether their university will delay a morning class, teachers planning lesson coverage, and parents coordinating child care can all use the same ZIP-code or city search to get a same-day read on the weather driving tomorrow's decision.
Most US school districts announce closures, delays, or early releases somewhere between 5 a.m. and 6:30 a.m. on the day of the storm, though some call it the evening before if the forecast is already locked in. Because of that, the most useful pattern is to check the calculator once the evening before to get a general sense of the storm, then again first thing in the morning for the most current snowfall and temperature numbers before your district makes its official announcement.
Checking closer to the actual morning matters because winter storms can speed up, slow down, or shift track overnight. A forecast that looked borderline at 9 p.m. can look very different by 5 a.m. once the snow has actually started falling or temperatures have dropped further than expected — so treat any single check as a snapshot, and refresh it as the morning gets closer.
Not really — that's the point of a web-based tool like this one. There's nothing to download and no account to create; you get the same instant snow day probability in your browser that a dedicated app would give you, without using up phone storage for something you'll only open a few days a year. It also works the same way on a phone, tablet, or laptop, so it travels with whatever device is closest at 6 a.m.
People often land here after checking AccuWeather or another general forecast app and wanting a more direct answer. A standard weather app is built to describe the atmosphere — snow totals, wind, temperature — and leaves you to interpret what that means for school. This calculator takes that same underlying forecast data and translates it directly into a single, easy-to-read percentage, which is the extra step most general-purpose weather apps don't take.
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