The best weather is expected in central and southern parts of the UK.
The east of England is set for scorching temperatures, with the mercury expected to hit 28C on Saturday and 30C on Sunday in Norwich.
London will see similar highs over the weekend, with 30C forecast in the north of the capital for Sunday.
However, things aren’t looking quite as bright up north.
Highs of around 14C are expected in the far north of Scotland, and 14-17C from Aberdeen through to Edinburgh.
Much of Saturday looks dry and bright but rain is expected later, and it will linger into Sunday.
The north east of England will be slightly drier and brighter, with highs of 20C forecast for the weekend.
However, rain is likely on Sunday afternoon.
Conditions will get warm and humid on Saturday before rain arrives on Sunday.
Temperatures in Manchester will hit 21C on Saturday and 18C on Sunday.
“Sunday looks very much as though it’s going to be a warmer day than Saturday”
Met Office forecaster Grahame Madge
Belfast will experience highs of 18C , with rain forecast for most of Northern Ireland over the weekend.
Things are looking brighter in east Yorkshire, where the mercury will peak at 22C on Saturday and Sunday.
Saturday will feel warm in the East Midlands with highs of 23C on Saturday and 21C on Sunday.
In the West Midlands, highs of 22C on Saturday and 21C on Sunday are expected in Birmingham, but rain could fall in parts of the region from Sunday afternoon.
Temperatures will peak around 21C on Saturday and 18C on Sunday through most of Wales.
Met Office forecaster Grahame Madge said: “The indication is that we could see highs of 28C (82F), isolated highs of around 28C, on Saturday, and the most likely candidate places for those would be places like Norwich, north London, those sorts of areas away from the coast, but in the south-east corner of the UK.
“And on Sunday we could see highs of 29C (84F), even possibly 30C.
“So Sunday looks very much as though it’s going to be a warmer day than Saturday. So we have got that warmth coming through.
“Once this warm front, and the air behind it, starts to pull across the UK then we will see temperatures starting to rise.”
However, the hot and humid conditions will lead to higher pollen counts and has triggered “thunder fever” fears.
The form of extreme hay fever occurs when there are thunderstorms and an abnormally high amount of pollen in the atmosphere.
These storms can absorb pollen grains and cause them to explode into tiny particles that are breathed in.
Dr Andy Whittamore, Clinical Lead and GP at Asthma UK, said: “If you have asthma and are already noticing more symptoms because of hay fever, such as coughing, a tight chest or breathlessness, make sure you keep your blue reliever inhaler with you at all times.
“Take hay fever medicines and your preventer inhaler (usually brown) as prescribed.”