Pick a place and you get three ensemble forecasts for it, two weeks ahead — the American model (GFS, 31 runs), the European one (ECMWF, 51 runs) and ECMWF's AI-based model (AIFS, 51 runs), each run many times from slightly different starting data. Four things get asked of them: how hot each day gets and how far it falls overnight, how much rain, how much thunderstorm fuel the afternoon builds up, and how hard it blows. Where the runs agree you can plan on it; where they spread apart, nobody knows yet.
The Castilian cities sit high — Segovia at nearly 1000 m — which is why their nights fall away so sharply compared with Valencia on the coast. In the Picos the question is usually the afternoon: a morning in the Cares gorge and a storm over Fuente Dé by four is a common enough shape. Looking for snow? The winter side has 49 ski resorts.
A model doesn't update continuously: it runs a few times a day — 00z, 06z, 12z, 18z — from a fresh snapshot of the atmosphere, and takes several hours to arrive after that. Between runs nothing here changes; when a new one lands the charts can shift. Each forecast says which run it is drawn from and when the next is due. Forecast data from Open-Meteo (GEFS 0.5°, ECMWF IFS ensemble 0.25° and ECMWF AIFS ensemble 0.25°).