BBC monthly outlook
Summary
June warmer than normal after an early cool spell
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Wednesday 3 June – Sunday 7 June
Pattern shift to a cool, wet end of the week
From Wednesday and for the rest of the week the UK will see a pattern shift that will bring some very different weather for everyone compared to that seen through April and May.
High pressure is expected to amplify in the Atlantic into the weekend, extending north nearer to Greenland and Iceland. This will help deepen an area of low pressure over Scandinavia and the North Sea. As a result, an unseasonably strong, cool northerly wind will develop for the UK and push a cold front south across the country on Wednesday. Western areas will see some outbreaks of rain and sharp showers on Wednesday, with perhaps a rumble of thunder or two. However, further east it will stay a bit drier but still turning cool by Thursday.
By Friday and into the weekend, however, the cold front will sweep into Central Europe and bring cooler, windier weather for the whole country. Some strong wind gusts are possible on northern and western coasts. Low pressure in the North Sea is likely to drift nearer on Saturday and Sunday, bringing some much wetter weather. After a warm, sunny, and dry week for most of the country, Saturday will be quite a change with a windy, wet, and cool day.
Monday 8 June – Sunday 14 June
A bit warmer and drier, showers in the south
The cool, wet spell from the first week of June will continue for a time into the second week, so showers, brisk northerly winds, and chilly nights are likely. This is not expected to last for the entire week, however, and by the end of the working week and into the weekend we expect the low pressure systems to drift south into Spain. This will allow pressure to begin to rise over the UK and bring some more settled weather for the northern half of the country. This will also allow some warmer southerly winds into southern areas, but also a few heavy or even thundery showers, especially by the weekend.
However, this does come with a rather large caveat: the exact timing of the low pressure system's departure. We expect it around midweek, making the second week of June a bit of a week of two halves. Shower, breezy, and cool to start with the second half being warmer than normal, dry, and sunny.
There is a risk that the ridge of high pressure is delayed in the arrival and the bulk of the week ends up on the cooler side of average with plenty of showers as low pressure systems move in from the northwest. But, at the moment, this is just a risk and not the preferred scenario. Confidence is medium mainly due to uncertainty on the timing of the pattern change, which will have a big impact on the expected weather. We have high confidence that the high will build in at some point and is likely to be in place by the weekend.
Monday 15 June – Sunday 28 June
Mostly dry and warm, particularly for the south
Once the high pressure ridge builds in from the Atlantic, it is likely to stick around for most of the rest of June and give us some similar weather to that just seen through May. Most of the UK will be sunny, warmer than normal, and dry for much of the second half of June.
However, we do expect that June will tend to be a slightly more changeable month than May or April were, so some brief wet, cool spells are possible, although these should last for more than a day or two. Scotland will be the main exception here and may well see more frequent outbreaks of rain from weak fronts.
The main risk to this scenario is that high pressure instead builds strongly to our north and northwest, perhaps near Greenland and Iceland like it is doing at the moment. This would let low pressure systems near Spain and Portugal move into the UK from the south and bring some thundery downpours. This would, however, also bring in some hot Mediterranean air, so it would still be a warmer than normal pattern. As such, confidence is a bit higher for a warmer than normal June, but low on the dryness and sunshine.
Sunnier summer months will see a sharp increase in the UV levels across the UK as we head into June as well.
Further ahead
June dryness is still shrouded in the fog on uncertainty, but next week we should be able to examine the second half of the month in greater detail.
https://www.bbc.co.uk/weather/outlook