30-day forecast · Belfast

Days 1-14: Fetched live from weather models (UKV, ECMWF, GFS) with statistical correction. Reliability ~85% for days 1-3, ~60% for days 7-10, ~45% for days 11-14.

Days 15-30: A real forecast does not exist that far ahead (a chaotic system). Instead we show season-typical values: the month’s average max/min from 1991-2020 climate data (London baseline with latitude correction for Belfast), with mild weekly variation.

Use: "Roughly how warm is it usually in London in the last week of July?" — a good question for days 15-30. "Will it rain on 27 May?" — no serious forecast can say.