BBC monthly outlook
Saturday 4 June—Sunday 10 July
Best of the weather in the south
The week starts with scattered showers over northern Scotland, while a humid and rather cloudy air mass spreads across England and Wales. The south will be mostly dry and feel quite warm, but some rain will move across Northern Ireland, northern England and southern Scotland. Tuesday will see a return to fresher conditions with some sunshine, but mainland Scotland and northeastern England can expect some heavy showers to develop.
Wednesday and Thursday will be dry and a bit warmer over much of England and Wales, while patchy rain will eventually spread to Northern Ireland and western Scotland. Friday too will be mainly dry before patchy rain returns to the northwest, and the weekend is set to be mixed, with an increasing threat of rain or showers spreading to most of the country.
Monday 11 July—Sunday 17 July
Winds and weather coming from the Atlantic
For the middle week of July the run of mainly westerly winds will continue. Occasional bands of rain will cross the country, followed by drier spells with sunshine but also showers in places. Over the south and east of the country the rain or showers will be short-lived, with plenty of dry weather, but for the northwest showers or some longer spells of rain can be expected on most days. Temperatures will be close to normal overall, but on the dry days the south will be rather warm. Friday marks St Swithin's day - the legend about forty days of rain or sun is not to be taken literally, but perhaps reflects that British summers do tend to get 'stuck' in the pattern that is prevailing around mid-July.
Monday 18 July—Sunday 31 July
No signs of a change in the weather pattern
So with this rather unsettled weather pattern in place, the most likely outcome for the last fortnight of July is for more of the same. We'll continue to see winds generally from a westerly quarter, occasionally bringing weather systems from the Atlantic eastwards across the British Isles. These will bring their rain or showers to all parts, but especially to Scotland and Northern Ireland where the intervening spells of drier and sunnier weather won't last very long. But over England and Wales there will be some lengthier dry spells giving sunshine and some rather warm days. A short hotter spell can't be ruled out, mainly affecting England, but this would bring an attendant risk of thunderstorms.
Next week
Looking ahead to early August - will summer sizzle or fizzle?
http://www.bbc.co.uk/weather/2635167#outlook