What the numbers mean.
The site transforms public NOAA station observations into historical comparisons. It does not reproduce WeatherSpark’s charts or methodology.
Weather observations
Daily precipitation for all four country editions comes from the NOAA/NCEI Global Historical Climatology Network Daily, a worldwide archive that incorporates national and regional station observations. NOAA/NCEI is credited as the distributor. Credit does not imply endorsement.
- Seasonal curve: share of valid observations with at least 0.04 inch of precipitation, for 1991–2020, smoothed with a centered 15-day moving average.
- Date ranking: a five-day window across 2021–2025, weighted 40% for the chosen day, 20% for each adjacent day, and 10% for each outer day. Recorded volume is used as a tie-breaker.
- Station choice: the nearest appropriate station in the app’s supported NOAA catalog. Conditions at a venue may differ from the station.
Place search
City, postcode, postal-code, and ZIP lookup uses the Open-Meteo Geocoding API, based on GeoNames data licensed under CC BY 4.0. Results are country-filtered and adapted to select a nearby GHCN weather station.
Known limitations
Historical frequency is not a forecast. Short recent samples can be noisy; incomplete observations, microclimates, elevation, station moves, and long-term climate change can all affect the comparison. Use the day page to inspect the underlying five-year observations.