On Saturday heavy thundery showers are forecast over east and northern England, with another area also seeing the same conditions in the South West.
The Met Office also warned of possible thunder and lightning over the weekend.
In between the showers on Saturday, there is a chance for some sunny spells.
While it wont be like the heatwave the UK experienced a few weeks ago, temperatures in London on Saturday will be around the mid-20s, with highs of 25C to 26C possible in some areas.
On Sunday, particularly for the east and North East, lots of low cloud, mist and fog is forecast for the start of the day.
There will also be some heavier rain in eastern and northeastern parts of the country.
Heaviest showers are likely to be in the west and the southwest.
Some regions will potentially see thunder and lightning.
Elsewhere on Sunday will also see some sunny spells and scattered showers, as Sunday is expected to be a slightly better day for much of the UK compared to Saturday.
Much of country is expected to see temperatures on Sunday in the low to mid-20s.
London is forecast to see highs of 23C to 24C.
The changeable weather pattern is expected to continue into next week.