UK heatwaves - data and advice

UK heatwaves are becoming more frequent, bringing prolonged periods of higher temperatures – which can seriously impact drivers.

Hot weather can cause vehicles to overheat and result in dehydration for the person behind the wheel.

In this driving in the UK guide, we look at the definition and what drivers should do during a heatwave.

What is a heatwave?

According to the Met Office, a heatwave is an extended spell of unusually hot weather for a particular area and time of year, sometimes accompanied by high humidity.

In the UK, a heatwave is officially recorded when a location experiences at least three consecutive days with daily maximum temperatures at or above a defined threshold.

These thresholds vary by region, ranging from 25°C in parts of Scotland, Northern Ireland, northern England, Wales and south-west England, to between 26°C and 28°C in central and south-east England.

Record temperature in England

Both England’s and the UK’s record temperature happened in Coningsby in Lincolnshire on the 19th July 2022 of 40.3ºC.

Record temperature in Wales

On the 19th July 2022, record temperatures were set in Wales in Hawarden, Flintshire at 37.1ºC.

Record temperature in Scotland

Charterhall in Scotland set record temperatures in the country on the 18th July 2022 with 34.8ºC.

Record temperature in Northern Ireland

Northern Ireland’s highest ever recorded temperature was 31.3ºC, which was set on 21th July 2021 in Castlederg, Country Tyrone. 

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Advice for driving in a heatwave

Driving in a heatwave can be both uncomfortable and risky, so preparation is vital.

Higher temperatures can affect both the driver and the vehicle, increasing the likelihood of a breakdown.

• Check your vehicle before travelling: Make sure that your coolant and engine oil is topped up – as well as your windscreen washer fluid. To help you with this, we have guides on how to check your coolant and how to check your oil
• Keep your tyres in good condition: Heat increases tyre pressure, so inspect them regularly. Also look out for any cracks or damage to the tyres and check the tread depth.
• Avoid driving at peak heat if possible: Check the weather forecast before leaving and try not to travel when the day reaches its highest temperature. Early mornings or in the evening are better options.
• Use sun protection: Sunglasses and sun cream are essential for drivers during the summer months – so make sure they are packed in the car.
• Air conditioning: Before the hot weather arrives, check your vehicle’s air con is working correctly. If the air blows warm or hot, the air con may need re-gassing.
• Take regular breaks: Drink lots of water and use rest stops to refresh and refocus.

Never leave pets in the car in hot weather. According to the RSPCA, even when it's 22 degrees Celsius outside, the interior of the car could reach 47 degrees within 60 minutes.

How many heatwaves does the UK experience every year?

According to the Met Office, there are between 4 and 10 heatwaves each year in the UK.

When is the next heatwave?

The UK is bracing for its fourth heatwave of the summer this week, with forecasters warning the latest spell of hot weather may not be the last before autumn arrives.

After a brief respite over the weekend, temperatures are set to climb once again, with parts of southern England expected to see highs of 32C to 33C by the middle of the week.

Several areas across southern and eastern England are forecast to meet the official heatwave threshold on Wednesday, with more regions likely to follow on Thursday as the hot air spreads. If forecasts prove accurate, it will mark the fourth heatwave to affect parts of the UK since May, capping what has already been an exceptionally warm and dry summer.

The Met Office is forecasting a pronounced north-south split, with southern and central parts of England enjoying prolonged sunshine and very warm conditions, while Scotland, Northern Ireland and parts of northern England remain cooler, cloudier and more unsettled with outbreaks of rain.

In response to the soaring temperatures, the UK Health Security Agency has issued a yellow heat-health alert covering the East Midlands, West Midlands, East of England, South East, South West, London and Yorkshire and the Humber. The alert comes into force at 9am on Tuesday and remains in place until 9am on Friday, with officials warning of possible impacts on vulnerable people, rising pressure on health and care services, and an increased risk of water-related incidents and wildfires.

The latest heatwave follows an already remarkable summer. Provisional Met Office data suggests July has been around 3C warmer than average across the UK, putting the month on course to rank among the hottest Julys on record. Meanwhile, much of southern England has seen exceptionally low rainfall, with some areas recording virtually no measurable rain throughout the month.

And there may be more hot weather to come. Met Office senior operational meteorologist Marco Petagna said there are early indications that conditions could become drier and more settled again as August progresses, raising the prospect of further heatwaves later in the summer.

Hottest temperatures by month in the UK

According to the Met Office, these are the hottest temperatures ever recorded in the UK for each month of the year.

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