Monthly Outlook

Unsettled weather should dominate from early to mid-September, with heavy rain, thunderstorms and rather strong winds possible at times.

After mid-month high pressure may build for a while and bring drier conditions.

Unsettled. Perhaps turning drier in the south

The rest of this week will have a changeable weather pattern. Further low pressure systems and associated fronts will pass near or across the UK, bringing periods of rain which could be heavy at times and potentially thundery, occasionally accompanied by rather strong and gusty winds.

Wednesday will be wet in many areas but by Thursday there should be a brighter interlude, with some sunshine in between a scattering of hit-and-miss showers. It will still be breezy, and more widespread rain should move into northern and western areas.

This band of rain could cross the rest of the UK during Friday but as a narrowing and weakening feature as it runs up against high pressure building to the south. Showers will follow elsewhere, most widespread and heaviest over western Scotland and Northern Ireland. The weekend has a chance of being dry in some southern regions of the UK while further rain affects the north and west.

Temperatures are going to vary from day to day but on average, despite the rain, they are more likely to be near or a little above normal for the week than below, and potentially warmer in the southern UK, especially later in the week.

Changeable. Possibly drier and cooler later

The second week of September should have similar conditions, with Atlantic weather systems still dominating the weather. As a result there should be further spells of wet and windy weather, with brighter and drier but potentially showery interludes.

The northern and western areas of the UK are likely to see wetter conditions than the south and east, where more normal amounts of rainfall are more likely. Temperatures are most likely to stay near or above normal.

By the end of the week there may be a change. High pressure could start to build but perhaps to the west of the UK, which may cause winds to temporarily come from a slightly cooler north-west to north-easterly direction. However, this might also deliver drier conditions with some sunshine and just a few showers dotted around.

Turning drier and warmer

After mid-September there are some signs that high pressure could build across the UK, leading to longer drier and calmer periods. Rainfall amounts should be below normal widely for the September 14th to 20th period, although conditions are unlikely to be completely dry.

Temperatures should increase, with above-average warmth most likely overall. A further boost to the temperature may come later in the month, between the 21st and 27th, if high pressure shifts to the south and east, and draws in more of a south-east to south-westerly flow, which might also lead to a little more rain later. That's uncertain though, and there is a low chance that high pressure will be centred more to the west or north-west, which might mean a slightly cooler but still fairly dry week.

On Friday we will look again at the chances of a drier conditions around mid-month, and the outlook will extend through the end of September into early October.

We will see if high pressure could move away and eventually allow low pressure systems to approach and bring a return to more unsettled weather.