The Netherlands has issued its first-ever Code Red alert for extreme heat, as the KNMI warns that Friday’s conditions could become life-threatening in multiple provinces. The warning begins at midnight as Friday starts in most of the country, leaving only four provinces under a lower “Code Orange” or milder status.

Under the Code Red warning, temperatures are expected to remain in oppressive ranges through the day, with the heat index reaching level 10—the maximum on the KNMI scale. The KNMI says the danger is not only the high temperatures but the combination of heat and humidity, which can cause dehydration, overheating, and heatstroke. It also highlights greater risk for groups including people over 75, young children, pregnant women, those who do manual labor, and people with underlying health conditions.

The guidance from the KNMI is strict: people should go outside only if it is strictly necessary, and they are encouraged to seek shade, drink water even if they are not thirsty, and limit physical activity. The meteorological service also urges people to pay attention to neighbors who may need help coping with the heat, and to closely monitor pets.

While much of the Netherlands is expected to see very hot conditions, the forecasts also indicate Friday and Saturday will be warmer than Thursday in several regions. The KNMI expects maximum temperatures to be in the mid to upper 30s for many areas, with the possibility of locally reaching about 40°C.

Officials warn that such heat can have wider consequences beyond health, including disruptions to daily life. The KNMI notes the weather can cause disturbances and social disruption, while hot conditions can also increase risks on roads and create hazards for people dealing with transportation and outdoor work. The alert comes as the country has already been under heat warnings for days, but this is the first time the most severe “Code Red” level has been used in the Netherlands.