Monthly Outlook

Temperatures will lift above average again through the first half of the coming week then cool closer to seasonal values. Unsettled weather will continue and will be wettest in the north at first and then in the south later next week and into the following one.

There is no sign of any notable heat for late summer or early autumn but conditions could warm somewhat by mid-September as high pressure potentially builds towards the UK. This would also make for drier conditions, although occasional frontal systems would still bring occasional rain especially to northernmost areas.

After a vigorous frontal system moves out of Scotland on Saturday the rest of the weekend will see a mixture of sunshine and showers. The cloudiest conditions and most of the showers will be over northern and western areas of the UK where it could also be misty for a while.

The first half of the coming week will be warm with peak temperatures in the south-east, where they will reach the mid to upper 20s Celsius. There will be showers or longer outbreaks of rain, some thundery, with wettest conditions in northern and western areas, while the south and east are relatively dry.

The second half of the week will become cooler after a low pressure system brings rain, a few thunderstorms and brisk winds southwards on Thursday. Temperatures will fall closer to the August average. On Friday and throughout the weekend, most of the rain and showers could become concentrated across Wales and England, with Northern Ireland and Scotland having longer dry periods.

With the longer-range models painting slightly different pictures, the outlook for the end of August and early September is uncertain. However, low pressure is most likely on the near-continent and it will occasionally push northwards. So at the moment it looks like the southern half of the UK will be wetter than the north.
High pressure will sit over the central-eastern Atlantic and this set up will mean that temperatures are most likely to be near average overall. So there is no sign of any burst of late summer warmth.

High pressure will try to build towards western Europe at times and there is a chance that this could force low pressure farther north, increasing the amount of rainfall across the UK. This scenario has about a 30% probability.

Uncertainty continues through the first half of September but there is a chance of a shift in the pattern, with Atlantic high pressure becoming more likely to build towards western Europe. This would push low pressure systems farther north, so the northern UK could become wetter and windier. Southern areas would also see a higher chance of drier and sunnier periods, although some rain is unavoidable at times.

It is possible that we will see a stronger build of high pressure by mid-September which would deliver drier conditions more widely. However, the northern UK, notably Scotland and Northern Ireland, could still be affected by passing low pressure systems.

Temperatures are most likely going to be near the September average but if this high pressure builds strongly then conditions could become warmer. At the very least there is no indication of any early-autumn chilliness.

The next round of long-range models might give us better clarity as we take another look at the end of summer and early autumn.