Weather Sources

Naola queries multiple weather services at the same time and combines their forecasts into a single consensus prediction. Here's how it works and which sources are used.

Current Sources

The free tier queries 3 sources. Naola Advanced adds 3 more for a tighter consensus, 6 in total.

ProviderForecast ModelTierWebsite
Open-MeteoECMWF (European model)Freeopen-meteo.com
OpenWeatherGFS (US model)Freeopenweathermap.org
Apple WeatherBlended (Apple)FreeApple Weather data sources
WeatherAPI.comBlendedAdvancedweatherapi.com
Visual Crossing WeatherBlendedAdvancedvisualcrossing.com
GoogleBlended (Google Maps Platform)Advanceddevelopers.google.com/.../weather

Home-screen widgets show the sources your plan includes, except Google, which appears only in the app.

How the Consensus Works

  1. All sources are queried at once: If one source is slow or down, the others still work. You always get a result.
  2. Forecasts are normalized: All temperatures are converted to Celsius and all wind speeds to m/s, so they can be compared fairly.
  3. A weighted median is computed: Sources powered by higher-quality forecast models (like the European ECMWF model) count more than blended models. This produces a more accurate consensus.
  4. Outliers are removed: If one source gives a wildly different reading, it's excluded from the final result to avoid skewing the consensus.

Confidence Colors

The colored badge on the weather card tells you how much the sources agree:

ColorWhat It Means
GreenHigh confidence: sources agree within 1.5 degrees C
YellowModerate confidence: some disagreement (within 3 degrees C)
RedLow confidence: sources disagree by more than 3 degrees C

Forecasts

The consensus approach also applies to forecasts:

How Source Accuracy Is Measured

The Source Accuracy screen ranks weather sources country by country, by how close their forecasts came to what weather stations measured. It is a personal tool to help you choose a source. It is not official or scientific, and it does not certify any provider. None of the weather services named below is involved in this ranking or endorses it. Here is the full method, so anyone can repeat it:

  1. Stations: In each country, a fixed set of reference weather stations, run by that country's national weather service and listed below. They are the same for everyone: the ranking never depends on where you search, and Naola keeps no record of where you look for it.
  2. Forecasts: Every day at 08:00 UTC, Naola records each source's forecast high and low for the next day at each station, using the station's own calendar day, and the Naola Consensus of those forecasts. Apple Weather, Google and WeatherAPI.com are never recorded, because their terms do not allow keeping their forecasts, so they are never ranked. The Naola Consensus ranked here therefore combines only Open-Meteo, OpenWeather and Visual Crossing Weather, and can differ from the consensus on your weather screen. Forecasts for Germany, France, Austria, Czechia and Japan are recorded at 08:20 UTC instead.
  3. Measurements: Each station's measured maximum and minimum temperature for that day is read from its national weather service once published, usually a day later (two days for France, about three for the United States). A few services define the day differently: SMHI's runs from 18:00 to 18:00 UTC, GeoSphere Austria's from 18:10 to 18:00 UTC and ČHMÚ's from 20:00 to 20:00 UTC; MeteoSwiss's and DWD's run from midnight to midnight UTC, and JMA's is the calendar day in Japan. Météo-France takes the low from 18:00 to 18:00 UTC, ending on the day, and the high from 06:00 UTC on the day to 06:00 UTC the next day. ČHMÚ and Météo-France do not publish these two windows: Naola inferred them from the services' own hourly or 10-minute readings. Each window still holds the day's afternoon high and early-morning low. Services can still correct recent values for a few weeks; Naola keeps the first value it reads, and for Japan uses only values JMA marks as normal quality.
  4. Score: For each source, station and day, the error is the difference between the forecast and the measurement, for the high and for the low, ignoring the sign, in °C. A source's score for a period is the average of those errors over all its stations and days.
  5. Ranking: Within each country, sources are ranked by their average score over the chosen period (7, 14 or 30 days), lowest first. A country's ranking is shown once it has 14 days of scores from at least 5 stations (or from all of them, in a country with fewer). Countries added later, such as Germany, France, Austria, Czechia and Japan, appear on the same terms.

Countries and stations

Station measurements: credits and licences

Attribution and Licences

Copernicus citations