Hour-by-Hour forecast as heat health alert issued for London heatwave

The alert will be effective from tomorrow (July 29) at 9am until Wednesday (July 31) at 11pm.

The alert warns residents to prepare for scorching temperatures that pose health risks, particularly to vulnerable groups.

Today’s forecast predicts a steady rise in temperature, starting at 21C at 11am, peaking at 26C by 4pm, and gradually cooling to 21°C by 11pm. 

Tomorrow promises even hotter conditions, with temperatures climbing from 17C at 7am to a high of 29C in the afternoon.

Clear skies will dominate the evening, maintaining warm temperatures around 23C by 11pm.

Residents are advised to stay hydrated and avoid strenuous outdoor activities during peak heat hours.

Looking ahead, Tuesday through Thursday will see variable cloud cover with sunny spells and an increasing risk of thunderstorms by midweek.

The persistent heat and potential for sudden storms underscore the importance of staying informed and prepared during this heatwave.

Here is the hour-by-hour forecast for today (Sunday)

11am – Sunny 21C

12pm – Sunny 22C

1pm – Sunny intervals 23C

2pm – Sunny intervals 24C

3pm – Sunny intervals 25C

4pm – Sunny intervals 26C

5pm – Sunny intervals 26C

6pm – Sunny intervals 26C

7pm – Sunny 26C

8pm – Sunny 25C

9pm – Clear 23c

10pm – Clear 22C

11pm – Clear 21C

Here is the hour-by-hour forecast for tomorrow (Monday)

7am – Sunny 17C

8am – Sunny 19C

9am – Sunny 20C

10am – Sunny 23C

11am – Sunny 25C

12pm – Sunny 26C

1pm – Sunny 27C

2pm – Sunny 28C

3pm – Sunny 29C

4pm – Sunny 29C

5pm – Sunny 29C

6pm – Sunny 28C

7pm – Sunny 28C

8pm – Sunny 27C

9pm – Clear 25C

10pm – Clear 24C

11pm – Clear 23C

Forecast in full

Today:

Early fog patches soon clearing to leave a fine day, with spells of sunshine. Cloud increasing by the afternoon but remaining bright. Feeling warmer than Saturday and more humid too. Light winds. Maximum temperature 27 °C.

Tonight:

Cloud soon thinning and breaking to allow a chance of some mist by the end of the night. Winds remaining light. Minimum temperature 14 °C.

Monday:

Another fine day after the clearance of any early mist. Some cloud developing with winds remaining light, Feeling very warm by afternoon. Maximum temperature 29 °C.

Outlook for Tuesday to Thursday:

Variable amounts of cloud and bright or sunny spells. Feeling very warm or hot in sunshine. Increasing risk of thunderstorms by Wednesday.