Hot Weekend Ahead: Heat Turns to Thunderstorms!

Weekend overview: hot air mass meets thunderstorm risk

A strong summer heat pattern is building over large parts of Germany and parts of Switzerland. Very warm to hot air is flowing in from the south and southwest, pushing daytime temperatures widely above 30 C and locally close to 40 C. At the same time the air becomes increasingly humid and unstable, creating the classic mix: heatwave first, then thunderstorms. This combination raises the risk of severe storms in many areas.

The basic story is simple and repeating: high pressure and hot air bring long, sunny spells and high heat stress, while heat and moisture feed powerful convective storms. Expect sweltering afternoons, warm nights in some places, and episodes of potentially severe thunderstorms that can bring hail, strong gusts and heavy rain.

Timing and regional forecast

Friday

On Friday the sun dominates first and temperatures climb into the low to mid 30s C for many. The first thunderstorms are expected to form in the west and northwest during the afternoon and evening as the air becomes more humid. These storms can be intense with localized very heavy rain and hail.

Saturday

Overnight the initial storm line will move east and weaken somewhat, but on Saturday daytime heating will allow storms to flare again in a broad band from the Eifel across Hesse and southern Thuringia into eastern Bavarian highlands. Temperatures will remain high, with many places around 30 to 35 C and some areas again higher.

Sunday

Sunday will keep the pattern of hot, humid conditions with scattered to repeated thunderstorms, especially in central and southern regions. Coastal and northern areas are likely to be a bit friendlier, but still warm. Overall the risk of showers and thunderstorms remains through the day.

Main hazards and impacts

The weekend threat is twofold: heat-related impacts and severe storm impacts. Heat leads to heat stress, sleep disruption during warm nights, higher risk of sunburn and strain on vulnerable people. Thunderstorms can produce heavy, short-lived rainfall, large hail, strong straight-line winds and frequent lightning.

1. Heat and humidity: prolonged high daytime temperatures above 30 C and locally up to near 40 C.
2. Heavy rain and flash flooding: intense downpours can overwhelm drains and cause local inundations.
3. Large hail: hailstones up to a few centimetres are possible in strong cells.
4. Strong gusts and wind damage: isolated storms may produce gusts over 100 km/h in severe cases.
5. Lightning: risk to people and outdoor equipment, and to structures such as stages and tall masts.

Local severity will vary, but several regions should be ready for events that can switch quickly from sunny to dangerous. Expect sudden heavy rain, hail and powerful gusts in the more intense thunderstorm cores.

Who will be most affected

Vulnerable groups include the elderly, people with chronic illnesses, young children and those doing strenuous outdoor work. Large outdoor events and festivals face particular challenges: hot days and warm nights combined with possible severe storms. Urban areas can suffer from heat stress and poor nighttime cooling. Geographically, the first thunderstorms will hit western and northwestern areas, then spread east and into central and southern parts, with parts of Baden-Wurttemberg and Bavaria at risk of very strong gusts within storms.

Practical safety tips

1. Stay hydrated: drink regularly and avoid sugary or alcoholic drinks during the hottest hours.
2. Protect from the sun: use high SPF sunscreen, wear a hat and light cotton clothing, seek shade at midday.
3. Secure loose items: tie down or bring in garden furniture, awnings and other objects that strong gusts can carry.
4. Prepare for heavy rain: keep drains clear, have waterproof clothing and sturdy shoes ready.
5. Know safe shelter: avoid trees, masts and open fields during lightning; a car is a relatively safe shelter if storms arrive.
6. Check local warnings and weather updates before travel and events, and follow official instructions.

For event organisers and festival-goers the advice is simple: plan for heat and storms. Provide water and shaded rest areas, encourage light clothing and sunscreen use, secure tents and equipment, and have a clear plan for when and where people should shelter if severe thunderstorms approach.

Outlook and what to watch next

Model guidance suggests the hot pattern could persist through the end of June with repeated hot spells and intermittent stormy episodes. Short coolings may be followed by renewed heat, so the hot-and-thunder cycle could repeat over coming days. Keep monitoring national and local weather bulletins, watch forecast maps and warnings on weather apps, and be ready to adapt plans at short notice.