After a brief break from the heat, the UK is once again seeing temperatures on the rise.
This week’s weather story is dominated by a developing heatwave, a marine heat anomaly, and a major leap forward in satellite meteorology.
A familiar pattern returns
If you’ve been enjoying the cooler conditions of late, brace yourself, change is on the way. The jet stream, which had dipped southwards and brought a spell of cooler, wetter weather, is now shifting. It’s arching north and dipping to the east of the UK, placing us firmly on the warmer side. That, combined with a strengthening area of high pressure building in from the southwest, is setting the stage for another hot spell.
This high-pressure system is compressing the air, allowing temperatures to rise steadily. With the sun beating down and little cloud cover expected, we’re likely to see temperatures exceed 30°C in parts of the southeast from Thursday onwards. And it won’t stop there, Friday and Saturday are shaping up to be the hottest days for many.
🌡️ Heat is building across the UK this week, temperatures could reach 32-33°C during the weekend 👇 pic.twitter.com/ugLnQjdOad
— Met Office (@metoffice) July 8, 2025
Not all heatwaves are created equal
There’s been plenty of talk about multiple heatwaves this summer, but the reality is more nuanced. While some areas have already experienced two distinct heatwaves, others, particularly in Scotland and Northern Ireland, have yet to meet the official threshold.
A heatwave is defined as three consecutive days where temperatures exceed a location-specific threshold. In mid-June, large parts of Wales and central England met that criteria. More recently, the Midlands, southeast and northeast England saw another round of heat. But many areas, including most of Wales, Scotland and Northern Ireland, have remained below the threshold.
This week’s heatwave is expected to be more widespread. Forecast models suggest much of England, eastern Scotland and eastern Northern Ireland will meet the criteria. Even areas that don’t quite qualify will still experience significantly above-average temperatures.
READ MORE: How to stay safe and cool in the heat
Where the heat will hit hardest
Temperature anomalies, how far above average the temperatures are, highlight the regional differences. While parts of East Anglia may be close to average, areas such as East Wales, southwest England and Yorkshire could see temperatures 8–9°C above normal.
Scotland is also warming up, with the peak expected on Sunday, particularly around the Moray Firth. Thanks to the Foehn effect, where air warms as it descends over mountains, temperatures here could reach 31-32°C, potentially challenging local records. Even the Outer Hebrides may approach record highs as the warmth pushes into the far northwest.
A second heatwave in the sea
It’s not just the land that’s heating up. Sea surface temperatures around the UK are also well above average, particularly in the English Channel where readings of 17–20°C have been recorded. Northern Scotland’s waters are closer to average, around 13–14°C.
Despite these elevated sea temperatures, they remain cool relative to the land. This contrast can lead to cold water shock for swimmers, especially as many head to the coast to cool off.
READ MORE: Waters surrounding UK experiencing significant marine heatwave
How long will the heat last?
Forecast models are in strong agreement that the hot weather will persist through the weekend. But what happens next is less certain. A cold front is approaching from the Atlantic, but ensemble models, which run multiple simulations, suggest it may not push through until early next week.
Spaghetti plots, which show the range of model outcomes, indicate a widespread in the position of the cold front. The European model places it across the UK by Monday, but most ensemble members suggest a slower progression. This means cooler air may not arrive until Tuesday or Wednesday.
Even then, temperatures in the south may remain in the mid to high 20s, suggesting the heat is not far away.
A new eye in the sky
Last week also brought exciting news from space. The MTG-S1 satellite, the second in the third generation of Meteosat weather satellites, was successfully launched from Cape Canaveral. This satellite will revolutionise how we observe Europe’s atmosphere.
MTG-S1 will provide 3D temperature and humidity profiles every 30 minutes, improving forecasts for thunderstorms, fog, mist and low cloud. It also carries the Copernicus Sentinel-4 sensor, which will enhance monitoring of particulates, wildfires and aerosols, key for public health and environmental research.
The satellite is currently in a transit orbit and will be fully operational within two years. Data should begin flowing by next summer.
A new satellite is scheduled to launch today in the latest phase of a multi-year project to transform weather forecasting and climate monitoring.
— Met Office (@metoffice) July 1, 2025
So what exactly is happening and why does it matter? Read this short thread, or check the story below 👇#MTGS1
🧵
The third heatwave of the year, or just the first?
— Met Office (@metoffice) July 9, 2025
Alex Deakin looks at which regions will be affected by this latest hot spell pic.twitter.com/LPdaynwSUi
Keep up to date with weather warnings, and you can find the latest forecast on our website, on YouTube, by following us on X and Facebook, as well as on our mobile app which is available for iPhone from the App store and for Android from the Google Play store.