Sunny skies are expected for runners crossing the finish line of the London Marathon on Sunday as forecasters anticipate the beginning of a warm and settled spell across much of the UK.

The Met Office said temperatures in the capital were expected to peak at about 22C on race day. Early conditions are likely to be cooler and more comfortable for runners as they set off in the morning.

In Manchester, also hosting a marathon on Sunday, similar conditions are forecast. Spells of sunshine and a high of 17C are expected.

Oli Claydon, of the Met Office, said conditions were expected to remain favourable. “It’s looking like the marathons for both Manchester and London will be dry. Temperatures shouldn’t be a problem for the morning, but the temperature will build during the day.”

The broader UK outlook is varied. Rain is expected to move across Northern Ireland and into the far west of Scotland and Cornwall overnight into Friday, accompanied by a southerly breeze.

Central and eastern regions of the UK are likely to remain dry, though areas of low cloud, patchy mist and frost may develop overnight under clearer skies.

By Saturday, a band of patchy rain is forecast to move eastwards across Scotland, England and Wales, followed by bright spells, particularly farther north. Conditions are expected to become increasingly warm and settled.

On Sunday, southern and eastern parts of the UK will experience dry weather and long spells of sunshine, while northern regions may continue to see scattered showers and increased cloud cover.

Highs of 24C are possible in the south-east of England by Monday, with further rises expected as warmer air is drawn up from continental Europe due to a blocked weather pattern – a mixture of high pressure to the east and low pressure to the west of the UK.

By midweek, temperatures are forecast to reach 25-27C in parts of south-eastern and central England, potentially marking the warmest weather of the year so far.

While such conditions are not unprecedented for April, they would be the highest recorded since 2018. The UK’s April temperature record of 29.4C, set in London in 1949, is likely to remain intact.

The spell of warm weather is expected to persist through next week, though a shift in the pressure systems may bring cooler conditions and the possibility of showers to some areas by next weekend.