SEASONAL INTELLIGENCE

See the seasons before they arrive.

Follow the climate signal from observed conditions into the seasonal forecast.

Normalized Diurnal Temperature Range — NDTR

(Tmax − Tmin) / Tmean
1991–2020 normal seasonal ensemble mean 10–90% range
ERA5-Land observed
Operational bridge
Seasonal forecast
1991–2020 climatology
Ensemble uncertainty

Seasonal boundaries are NDTR-derived energetic transitions. The ECMWF seasonal forecast is a regional 36 km signal, not a street-scale city forecast.