Saturday
Slack pressure exists across Britain, with light winds for most places. Hazy sunshine will give way to some building cloud through the day, and a scattering of locally heavy downpours and thunderstorms will form through the afternoon. These very hit and miss, but will move around slowly. A fresh easterly breeze along the south coast. Northern Scotland sees rain become persistent. Highs 18 to 24C.

Saturday night
A cold front will sink southwards overnight, bringing much chillier air down from the north. A zone of rain with some showery bursts will pass southwards, this falling increasingly as snow over northern hills. Strengthening northeasterly winds developing. Temperatures ranging from a balmy 12C in the south, down close to freezing in northern Britain by dawn on Sunday.
 

Sunday
Cold air sweeps southwards across the country. Showery across the north and east, with hail and snow, not just confined to the hills - in northern Scotland snow may lie to low elevations for a time. A fragmenting band of rain will drift south over England and Wales, but may allow some heavy showery bursts to break out over central and southern counties through the day. A brisk north to northeasterly wind. Temperatures only 6 to 10C in the north, may stay at 13 to 16C in far south.

Monday
High pressure to the northwest of Britain draws in a cold Arctic air mass across the country. Strong north to northeasterly winds will feel distinctly chilly for early May. A scattering of showers affect northern Scotland and eastern counties of England, these of hail, or snow over the hill tops. Generally dry with sunshine across central and western regions. A chilly start with frost in sheltered spots. Highs only reaching 9 to 13C.