I'm not sure where Yahoo get their UK weather forecasts, but BBC states
it's "in association with the Met Office".
I check both when I need a reasonable idea of what the weather will be
like, and always find the BBC predicts much more pleasant conditions
than Yahoo does. From today's 5-day forecast, for example,

Yahoo's forecast by my postcode, then (BBC's) by my home town:
Today: mostly cloudy (sunny intervals) Max temp 2°C (3°C)
Friday: snow (light rain) Max 2 (5)
Sat: rain/snow (light rain) Max 2 (5)
Sun: cloudy (sleet) Max 3 (7)
Mon: rain & snow (sunny) Max 3 (8)

I realise that forecasting isn't an absolute, guaranteed thing, but
there's a pretty big diference between 3°C and 8°C for the same day, and
between rain & snow and sunny. I have a fairly expensive (gifted!)
"weather station" which tends to support Yahoo's forecast over 24-48
hours, but my thinking was that the Met Ofice was more "authoritative"
than Yahoo's unnamed source of info... And you DO get better weather
from the BBC, so I'll certainly go with them next Monday!

Another (mainly Scottish) gripe: on ITV and BBC equally, it's often very
hard to know where the weather forecaster means when (s)he uses, very
frequently, the vague term "in the north". Is it north of England, or
north of the UK (meaning northern Scotland, presumably - or maybe the
whole of Scotland - and maybe bits of N England too)? Sometimes it's
clear from the forecaster's gestures, sometimes it's not, and we can't
see the gestures on the radio.

Rab