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Heat 4/5 high METEOALARM

Heat warning level 4: Monthey - Val d'Illiez

Unchanged since the first report last verified 18:13 CEST

Summary

A level 4/5 heat warning is in effect for Monthey - Val d'Illiez due to persistently high temperatures. Circulation and health are under significant strain.

What hazard threatens

Persistently high day and night temperatures strain the circulation and favour dehydration, heat stroke and health emergencies, especially for the elderly, infants and the sick. The risk of forest and wildfires also rises.

Local weather conditions

Measuring station Les Marécottes, 990 m a.s.l., 11 km from the event

Measurement taken 855 m below the altitude of the warning area (1845 m a.s.l.).

Temperature

27.0 °C

When the warning was issued · 29.07.2026 12:00 CEST

Daily maximum

30.1 °C

on the day of the warning

Humidity

48 %

When the warning was issued · 29.07.2026 12:00 CEST

Day of warning and following days

  • Wed 29.07. 30° 20° measured

As of: Values as at the time of the warning; they are not updated afterwards.

Source: MeteoSwiss

Context & protective measures

Background: heat waves are becoming more frequent and intense in Switzerland. The greatest danger is the health burden from persistently high day and night temperatures, which favour dehydration, heat stroke and circulatory problems. The elderly, the chronically ill, pregnant women and infants are particularly at risk.

Recommendation

Likelihood is medium, impact is high. Drink enough, avoid the midday heat and physical exertion outdoors. Keep living spaces cool by ventilating at night and in the morning and shading during the day, and look after vulnerable people around you.

What to do now

Drink enough right now, shift outdoor activities to cooler times of day and observe any fire bans in place. Check whether vulnerable people near you need support.

Risk matrix

Event location

Coordinates · WGS84
46.1860° N, 6.9167° E
46°11′09.5″ N   6°55′00.0″ E