Forecast Verification
How closely recent temperature forecasts matched temperature observations at Ferny Grove.
LACO (Local Atmospheric Corrected Output) is the locally corrected forecast used on this site. It combines guidance from several major weather models, learns from recent performance at Ferny Grove, and produces a single combined local forecast.
Recent temperature accuracy
What the results generally show
The headline mean absolute error is a broad summary across complete verified forecasts; it does not mean accuracy is the same throughout the forecast horizon. Temperature accuracy generally decreases as the forecast extends further ahead, so the lead-day results below provide the more useful view. Local correction has been most beneficial during the morning and afternoon, when uncorrected model guidance has shown the largest systematic errors. Daily minimum and maximum temperatures have different error patterns, and not all corrections improves every forecast.
Temperature accuracy by forecast lead day
Lower mean absolute temperature error indicates a more accurate forecast. Bias shows whether forecasts tend to be too warm or too cool.
Share of hourly forecasts within each error threshold
These percentages are shown by lead day because a single percentage across the full forecast horizon would conceal the difference between near-term and longer-range accuracy.
Hourly-derived daily minimum and maximum temperature accuracy
These results compare the lowest and highest matched hourly forecast and observed temperatures on each complete calendar day.
Daily minimum and maximum temperatures within ±2 °C by lead day
Minimum and maximum temperatures are shown separately because their accuracy differs.
How verification works
Each hourly temperature forecast is matched with the temperature observation recorded for the same hour. Only complete calendar days are included. All errors and thresholds shown on this page relate to temperature and are expressed in degrees Celsius.
Data sources and attribution
Forecast guidance is provided through Open-Meteo using models from ECMWF, NOAA, Deutscher Wetterdienst, Environment and Climate Change Canada, the Japan Meteorological Agency, the UK Met Office, the Korea Meteorological Administration, Météo-France and the China Meteorological Administration. Observations are recorded by the Ferny Grove Weather station.
Weather model data by Open-Meteo.com, used under the CC BY 4.0 licence. The source model guidance has been combined and locally corrected; these changes are by Ferny Grove Weather and are not endorsed by Open-Meteo or the originating agencies.
Temperature verification describes past performance and does not guarantee the accuracy of an individual future temperature forecast.