BBC monthly outlook
Summary
Unsettled for much of July
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Wednesday 26 June – Sunday 30 June
Dry, very warm week. Hot Saturday. Wet Sunday.
High pressure extending into the UK from the north-west will keep things fine and dry for the latter half of the working week. There will be plenty of sunshine with some patchy cloud in places, especially in the afternoons. A fresh, northerly breeze on the East Coast of Britain will keep things feeling a bit cooler there. An ongoing heatwave in Europe will stay largely confined to Europe through Friday, with high pressure over the UK preventing the hot air from spreading its way across the whole of the country. However, southwest and central southern England along with south Wales will see some of this air, lifting temperatures into the upper twenties for the end of the week.
The air will also be quite humid, so afternoons will feel a bit muggy out in the sun. Elsewhere it will be less humid, with temperatures nearer to average or a touch below in Scotland. On Saturday, our high pressure block will move off to the east and winds will shift from easterly to southerly, allowing the hot air from France to move up into the UK. Central and eastern counties of England and Southeast Scotland are expected to see highs well above average, with Southeast England reaching up into the low thirties. This air will also be very humid, so Saturday will feel very muggy and oppressive in the afternoon for most. A few sharp showers are expected in the West and across Scotlan,d that may provide a bit of relief. Overnight and into Sunday, a cold front will then sweep across the UK from the northwest, bringing some heavy or thundery showers overnight to the North, but more notably, bringing in some cooler and less humid air for Sunday. Most places will see temperatures return to average, with highs in the low to middle twenties.
Monday 1 July – Sunday 7 July
Wet for a time, but drying out later in the South.
After the cold front on Sunday, the UK will be dominated by a progressive, westerly weather pattern with a cooler westerly breeze bringing scattered showers to westernmost counties through the first half of the week. Scotland will likely see weak fronts keeping the northern half of the country cloudy and damp, with showers for the southern half. Central and eastern counties of England will likely stay mostly dry but with patchy cloud and sunny spells. The odd shower cannot be ruled out, mainly in the Midlands and central southern England. From Wednesday and through the rest of the week and weekend, a ridge of high pressure is expected to build in from the southwest, bringing with it some warmer and more settled weather.
Temperatures will likely climb to slightly above average in the South with mostly sunny skies, light winds, and dry weather. However, high pressure will struggle to reach too far north where more persistent lows will linger near Iceland and Scandinavia, so northern Scotland is expected to stay mostly cloudy and damp with weak fronts overhead for much of the time. This high pressure is not expected to be a long-lived feature for the rest of July, and towards the end of the weekend we will likely see it start to slide off to the west or southwest, allowing low pressure to return perhaps as early as Saturday. This will bring in some wetter and cooler weather, although temperatures will not be too far below average so it will still feel warm in the afternoons.
Monday 8 July – Sunday 21 July
Unsettled weather returning for the rest of July.
As high pressure gradually weakens and retreats into the North Atlantic, low pressure tracks are expected to return to the UK into mid-July and linger into late-July, keeping the summer more unsettled, wet, but still warm at times. As the jet stream - a current of fast moving air high in the atmosphere that drives weather systems - dips south into Europe, low pressure centres will move near or over the UK, keeping things cloudier and wetter than a typical July.
There is a risk that we may see one of these low pressure systems drift off to the southwest similar to the last week of June, allowing it to tap into some hot Saharan air and trigger another heat wave. However, confidence is low on this happening, and on any exact dates at this range. There is the chance - around 30% - that high pressure will become more dominant across Central and North Europe, including the UK, bringing in some warmer tropical air and sunnier, drier and more summer-like weather. However, we expected low pressure to be the main weather player for much of July, similar to how it dominated the weather through most of June, making for quite a different summer to what we saw last year!
Further ahead
We will have a good idea of how hot the weekend will get to close June, and take a further look at the expected wet July.
https://www.bbc.co.uk/weather/outlook