Monthly outlook
The last update time is May 21 (Friday) 16:50 BST
Generalize
Usually more unstable than normal.
The unusual storm in May is approaching, heralding the cool beginning of the weather summer, and the usually unstable cooling pattern lasts until June.
The high-pressure system built from the southwest can sometimes disrupt this pattern, but these tendencies are often short-lived settlement spells.
Rain usually comes in the form of strong showers or thunderstorms, but there may be more out-of-season storms around mid-June.
Although the weather is more likely to become warmer in the future, it seems that the weather in June will be cooler than usual and more like spring.
Saturday, May 22-Sunday, May 30
The wind calmed down, but remained cool and unstable.
After an unseasonable stormy weekend in late May, the wind speeds next week seem to be more stable.
Throughout the week, high pressures may develop in the west of England, pushing the lows of the Atlantic Ocean from the weekend into Scandinavia.
A cool northerly wind will follow, which will keep things trending below average, thus continuing the cool May trend.
There may be sporadic showers in the north and east, and sometimes thunderstorms.
The bank holiday weekend looks drier and sunny, but it still feels cooler than usual.
Monday, May 31-Sunday, June 6
The chance of sporadic afternoon showers is increasing.
The high pressure of the bank holiday weekend will gradually begin to slide to the southwest in early June.
However, this may take most of the week, so a lot of drier and sunny weather is expected.
The low pressure from Scandinavia will eventually enter Britain from the east, which makes things increasingly unstable.
First in the eastern region, but eventually in most parts of the country.
Rain usually comes in the form of sporadic showers or thunderstorms, rather than rainy storms.
With the low pressure in the east and the high pressure in the southwest, large-scale weather patterns help drive north or northwest winds throughout the week.
This will keep the temperature below average and introduce air from Iceland and the North Atlantic.
Our best option is to enable us to enter the subtropical Atlantic or African air, so as to get warmer, more summer-like temperatures, and to do this, we need southwest or south winds.
The main alternative in early June was that the high pressure remained overhead rather than transferred.
This is still a cool mode, but it will stay dry and stable throughout the week instead of showers.
Subtropical air may be filtered to the western region, but this is considered unlikely. We are confident that the temperature will be lower than normal, but have moderate confidence in the showers later this week, because there is still a 30% chance of maintaining high pressure.
Monday, June 7-Sunday, June 20
The weather is very changeable, keep it cool.
It is expected that by mid-June, a rather volatile pattern will appear across the Atlantic and Europe.
The rain pattern can be changed up, down, left and right, but the temperature is much more consistent.
The overall pattern of low pressure in the east and high pressure in the west or southwest is expected to remain unchanged.
This will continue to promote northerly winds and lower than average temperatures within a month.
The variability comes from the high-pressure and low-pressure systems competing for control of the UK. There is no clear signal that these two months will be dominant.
On the contrary, we expect widespread low pressure from Scandinavia to bring unstable cool weather, and high pressure buildings in the southwest will occasionally interrupt these weather.
When the low pressure is brought under control, there will be greater chances in the out-of-season windy days at the forefront of Atlantic weather.
There will also be plenty of sunshine and showers.
When the high pressure is over, it will be more stable, sunny and dry, but it will still feel cooler for June.
When we may see high pressure, it is difficult to time, and computer models are facing very challenging moments.
We are very confident that although the pressure system has changed, the temperature will still be below average.
The risk situation is that high pressure is kept firmly under control throughout the month, keeping it dry and sunny.
This also makes the risk of warming later this month less and less.
If the high pressure is transferred to Germany, we may be able to blow southerly into the high temperatures of Africa.
We expect a 30% chance of drier, high-pressure mode, and only 10% chance of a very warm southerly wind.