Our Weather Data Sources
Every snow day prediction on Summersnowday is built on data from the world's most trusted meteorological agencies — the National Oceanic and Atmospheric Administration (NOAA), the National Weather Service, and supplementary commercial feeds. No guesswork. No made-up numbers.
📊 Data Coverage at a Glance
Our prediction engine aggregates meteorological data from four primary source tiers, covering the continental United States, Alaska, Hawaii, and all Canadian provinces and territories.
🏛️ Primary Source 1 — NOAA (National Oceanic and Atmospheric Administration)
The National Oceanic and Atmospheric Administration (NOAA) is the foundational data provider for all U.S. weather predictions on Summersnowday. Established under the U.S. Department of Commerce, NOAA operates a network of thousands of observation stations, weather balloons, satellites, and ocean buoys that collectively form the most comprehensive atmospheric dataset in the world.
National Oceanic and Atmospheric Administration
Primary US Data SourceNOAA's operational forecast models — including the Global Forecast System (GFS) and North American Mesoscale (NAM) model — provide the backbone of our 72-hour outlook. These models ingest millions of atmospheric observations per day and are run four times daily by NOAA's National Centers for Environmental Prediction (NCEP).
- Global Forecast System (GFS) model output — 0.25° grid resolution
- North American Mesoscale (NAM) model — 3 km CONUS domain
- NOAA Winter Weather Outlooks and Watch/Warning bulletins
- Cooperative Observer Network (COOP) surface observations
- Automated Surface Observing System (ASOS) real-time data
📡 Primary Source 2 — National Weather Service (NWS)
The National Weather Service (NWS), a division of NOAA, operates 122 Weather Forecast Offices (WFOs) across the United States, each responsible for issuing hyper-local forecasts for their geographic service area. The NWS provides Summersnowday's most granular location-specific forecast data through its public API.
National Weather Service — weather.gov
Primary Real-Time Forecast APISummersnowday queries the NWS public API (api.weather.gov) for every user location lookup. This API returns official gridpoint-level forecast data at 2.5 km resolution — far more precise than any generic weather service. The NWS API is maintained by the U.S. federal government, is free to access, and carries no commercial bias.
/gridpoints/{wfo}/{x},{y}/forecast— 7-day period forecasts/gridpoints/{wfo}/{x},{y}/forecast/hourly— hourly breakdown for the critical 6–9 AM window- Active Watches, Warnings, and Advisories (Winter Storm Watch, Blizzard Warning, Winter Weather Advisory)
- Snowfall probability grids and quantitative precipitation forecasts (QPF)
- Wind chill and apparent temperature grids
🌦️ Supplementary Source 3 — AccuWeather
AccuWeather is one of the world's largest and most recognized private weather forecasting companies, headquartered in State College, Pennsylvania. Summersnowday references AccuWeather's published winter weather outlooks and precipitation probability data as a secondary validation layer when NWS model runs show significant forecast uncertainty.
AccuWeather
Secondary Validation Layer — USAAccuWeather operates its own proprietary forecasting models, which run independently of the NWS and NOAA operational suites. When our confidence-scoring system detects high inter-model variance (NWS and NOAA models disagree on snowfall by more than 2 inches), we reference AccuWeather's public snowfall forecasts and winter storm impact scores as a third-party "tiebreaker" signal.
- AccuWeather MinuteCast® precipitation onset timing
- Winter Storm Severity Index (WSSI) public advisories
- 24-hour and 48-hour snowfall total forecasts
- Road weather impact assessments published by AccuWeather's expert forecast team
🍁 Primary Canadian Source 4 — Environment and Climate Change Canada
For all Canadian province and territory predictions, Summersnowday pulls data from Environment and Climate Change Canada (ECCC), the federal agency responsible for official weather forecasting, warnings, and climate data for Canada. ECCC is the Canadian equivalent of NOAA/NWS.
Environment and Climate Change Canada — weather.gc.ca
Primary Canadian Data SourceECCC's Meteorological Service of Canada (MSC) maintains a network of 8,000+ weather observation stations and operates the GEM (Global Environmental Multiscale) model suite. Canadian school closure predictions on Summersnowday use ECCC's dataMart API feeds, which provide bilingual official forecasts for all Canadian communities.
- MSC Datamart real-time NWP model outputs (GEM-Global, GEM-Regional, GEM-HRDPS at 2.5 km)
- ECCC Severe Weather Warnings — Special Weather Statements, Winter Storm Warnings, Blizzard Warnings
- Hourly Surface Weather Observations from MSC stations
- Snow depth and snow water equivalent analyses
⏱️ Data Freshness & Update Schedule
Stale weather data is dangerous for a snow day prediction service. Here is our exact refresh schedule for each data tier:
🚫 What We Do Not Use
We believe transparency includes disclosing what we intentionally exclude. Summersnowday does not use the following as prediction inputs:
- Social media posts or crowdsourced reports — unverified and unreliable for probabilistic scoring
- Advertising-driven "weather apps" that profit from sensationalized forecasts
- Historical school closure lists scraped from news as a sole input — we use them only for regional threshold calibration, not real-time scoring
- AI language model hallucinations — all weather data is fetched from authoritative APIs at query time; no values are fabricated
Ready to See Our Data in Action?
Enter your ZIP code now and watch NOAA, NWS, and our regional models combine into a single closure probability — updated in real time.
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