London will see temperatures rise to 30C on Friday after well above-average rainfall figures in the first half of the month.

Met Office spokesperson Nicola Maxey said night-time temperatures could stay in the low 20s for parts of south-east England – officially classified as “tropical nights” if they do not drop below 20C. 

She said there was still uncertainty over how soon the milder conditions would come in, with the possibility that the South east could retain its heat a little longer than elsewhere.

Meanwhile, parts of the country have already well-exceeded July’s average rainfall figures despite only being hal

fway through the month.

The Met Office spokesperson said London has had 154 per cent of its July average rainfall already.

Ms Maxey said: “There are quite big regional differences but overall it’s looking like a wet month so far.

“There is a caveat that, with a dry couple of weeks, by the end of the month things could even themselves out.”

She said that two or three heavy downpours often caused much of a location’s July rainfall totals, rather than a prolonged period of wet weather.

St Swithin’s Day on Monday – traditionally said to predict the next 40 days of weather – was another wet one for much of England and Wales.

But the Met Office said conditions next week would be “changeable” rather than just rainy, with temperatures close to average.

Here is the forecast for London in full

Today: A grey and overcast morning for many with overnight rain continuing, although mostly light and sporadic by this point. This clears eastwards into the afternoon, with showers then following as well as a few late sunny spells developing. Maximum temperature 22 °C.

Tonight: One or two showers lingering through into the evening, but these dying off overnight with clear skies developing for the second half of the night. Minimum temperature 11 °C.

Wednesday: Fine and dry on Wednesday with patchy cloud and plenty of sunny spells. Light winds and sunshine should see temperatures around average for time of year. Maximum temperature 26 °C.

Outlook for Thursday to Saturday: Sunny spells and isolated showers expected on Thursday, dry on Friday. After a dry start on Saturday rain is expected to move in. Possibly feeling very warm on Friday.