Updated 20th September - Covering 26th September - 18th October 2022
Temperatures will tend not to be far from normal overall, coming out around 0.5C above the 1991-2020 average in most regions. Week 2 is expected to be slightly cooler than average, but the rest of the forecast period is expected to be a little warmer than average.
It will be drier than normal in most parts of the UK, particularly in central and southern parts of both England and Wales, but with rainfall coming out closer to normal further north, probably near to slightly below average for much of Scotland.
Most of England and Wales will be sunnier than average, with the possible exceptions of north Wales and north-west England. For much of Scotland and Northern Ireland, close to average sunshine looks more probable.
This period will be dominated by north-westerly winds, with high pressure in the eastern North Atlantic and low pressure over Scandinavia. The week will start off with high pressure ridging into southern parts of the UK, bringing slightly above-average temperatures for the time of year. It will be generally cloudy in most western and northern parts of Britain and some rain especially for western Scotland, while for eastern and southern England it will tend to be dry with some sunshine during these warmer westerly spells.
However, as the week progresses we will increasingly see frontal systems pushing in from the north-west. These will bring bands of rain southwards across the country, though again rainfall amounts from these will tend to be small in the south. It is expected that by the latter part of the week we will be seeing some cold northerly and north-westerly outbreaks bringing a mix of sunshine and showers, with northern parts of the UK generally seeing the most showers, and southern and especially south-eastern parts of the country staying mainly dry and sunny.
Relative to the 1991-2020 reference period, temperatures are forecast to be slightly below average for much of the UK due to the emphasis on north-westerly winds, but probably not by more than 1C.
Rainfall totals are expected to be close to normal in most parts of Scotland and northern England, and below normal in Northern Ireland and in Wales and central and southern parts of England, particularly the south-east.
Sunshine is likely to be above normal in most parts of the UK, especially in the south, but possibly close to or just below normal in the northern half of Scotland.
It looks probable that the high pressure to the west of Britain will push eastwards and bring a more settled spell of weather early in the week, with dry and predominantly sunny weather and some cool nights early in the week. It will tend to warm up somewhat from the west and south-west as the high pressure becomes centred to the south-east of Britain, but these warmer air masses will most likely produce cloudier weather, especially in Northern Ireland, western Scotland and north-west England. Sheltered eastern parts of the UK will probably hold onto a fair amount of sunshine for much of the week, though particularly towards the south and south-east, where the high pressure will tend to dominate for much of the week, some fog patches are likely to form overnight which may be slow to clear in places.
Temperatures are thus forecast to be above average overall in spite of the cool start to the week, though not exceptionally so, with most regions coming out about 1C above average. Rainfall will generally be below normal, although there is potential for rainfall to be nearer average in north-west Scotland due to a west to south-westerly type developing across the north. Sunshine is expected to be near or rather below normal in Northern Ireland, western Scotland and north-west England, but generally above normal in most other regions, especially the east.
This period is expected to start off with relatively unsettled weather pushing in from the north-west, but there is plenty of uncertainty over how long this will establish for. It is likely to start off warmer than average with south-westerly winds, but with temperatures tending to be close to average later in the period with a likelihood of mainly westerly or north-westerly winds. High pressure is likely to continue to ridge into southern parts of the UK at times, maintaining drier than average weather across the south, but with a greater chance of north-western parts of the UK being affected frequently by rain belts and showers coming in off the North Atlantic.
For the period as a whole, mean temperatures are most likely to be slightly above average, typically by around 1C. Rainfall is most likely to be below normal, especially in the south, but with more uncertainty over rainfall totals for the north of Britain. Sunshine totals are likely to be above average in most eastern parts of the UK and probably near average in most western areas.
Monthly weather forecast
The month ahead forecast is written by Ian Simpson and is updated every Monday.