How It Works
Everything you need to know about how we track forecast accuracy across 2,200+ locations worldwide.
What is ForecastAdvisor?
We help you find the most accurate weather forecaster for your location. Powered by ForecastWatch, we've compared billions of forecasts from major consumer and government weather services against actual observations for over 2,200 locations worldwide since 2004.
What are the award winners shown on forecast pages?
Forecast pages in regions with conferred awards show the ForecastWatch Most Accurate Forecast Award winners for that region. The awards are based on twelve months of independent accuracy evaluation by ForecastWatch across the region. The seal and winner cards link to the award pages on forecastwatch.com.
How is forecast accuracy measured?
ForecastWatch compares millions of forecasts of temperature, precipitation, and wind against what was actually observed at weather stations around the world. Each provider is scored over a full twelve months, so a lucky stretch does not decide a winner. The awards shown on this site come from that evaluation. The full methodology is described in the ForecastWatch awards methodology.
My city isn't one of your 2,200 locations. How does accuracy work?
We find the nearest location where we have accuracy data. If it's within 50 km of your city, we show the results directly. If it's farther away, we note which location the data comes from. Weather patterns are generally similar within this range, so the results are still meaningful.
Where does the forecast on each city page come from?
The 5-day forecast displayed on each city page comes from Open-Meteo, an open-source weather API. It's provided for convenience — the accuracy comparisons are what ForecastAdvisor is really about.
What time period does the accuracy data cover?
Accuracy is based on a rolling 12-month window, updated monthly. This gives a large enough sample for meaningful comparison while reflecting each provider's current performance.
How do you collect weather forecasts?
We collect forecasts daily from major weather providers' websites and APIs for over 2,200 locations worldwide. Collection order is randomized to prevent any provider from having a systematic timing advantage.
Where do you get the actual weather observations?
Observations come from quality-controlled weather station data, verified with over 50 automated validity checks. We cross-reference temperatures, precipitation, and other measurements against historical ranges and neighboring stations.
Why are low temperature forecasts less accurate than highs?
Low temperatures are forecasted for roughly 12 hours further into the future than highs, making them inherently harder to predict. Overnight lows also depend heavily on cloud cover and wind patterns that are difficult to model precisely.
What is weather changeability?
Changeability measures how much the weather varies from one day to the next at a given location. We track day-to-day temperature swings and precipitation transitions, then rank locations from most to least changeable. You can explore this data on any city page or on the Changeability page.
How is ForecastAdvisor different from ForecastWatch?
ForecastWatch provides detailed forecast accuracy analytics to weather industry professionals and providers. ForecastAdvisor is the free, public-facing side — giving consumers a simple answer: who gets your weather right?