Summer day: It will be 28 degrees warm at the weekend – News

T-shirt, sunglasses and lots of sunscreen: From Friday to Tuesday the 20 degree mark will be broken. On Saturday we can even expect the first summer day of the year with temperatures over 25 degrees. Simon Eschle from SRF Meteo classifies the highly unusual temperatures in April.

Simon Eschle

Meteorologist SRF Meteo

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Simon Eschle is a meteorologist at SRF. He has a bachelor’s degree in geography from the University of Zurich and a master’s degree in atmospheric sciences from ETH Zurich. He has been with SRF Meteo since June 2022.

SRF News: Switzerland will be catapulted into summer this weekend. How is this meteorologically possible?

Simon Eschle: A high pressure area will come to us from Friday. On the one hand, this brings warm air from the south, and on the other hand, the air sinks in a high pressure area. As it sinks, the air compresses and heats up. In the Alps there is also a foehn, which also helps.

What is a summer day?

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If at least 25 degrees are measured, in meteorology it is called a summer day. At least 30 degrees is considered a hot day.

How warm will it be?

On Saturday we are currently expecting highs between 25 and 28 degrees. So it would be enough for a summer day. It would be the first day of summer this year. In the south there is probably not enough for a summer day. It is also warm at altitude: at 2000 meters it is around 16 degrees on the weekend.

It is also warm at altitude: at 2000 meters it is around 16 degrees on the weekend.

Can you already swim in the lakes?

It’s fine for the more hardcore, otherwise the lakes are still cold. The large lakes in the north are around 8 degrees. This applies, for example, to Lake Zurich, Lake Constance, Lake Geneva and Lake Thun. Lake Lugano is warmer at around 12 degrees.

Two women sunbathing by the lake.


Sunbathing is possible on the weekend – but bathing in water still takes courage.


Will it cool down quickly in the evening?

Not so fast. At eight o’clock in the evening the temperatures on the weekend are usually still above 20 degrees. In the morning hours there are lows between 7 and 11 degrees, and it is even warmer in the Föhn valleys.

Heat records in spring

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Earliest summer days on the north side of the Alps:

  • March 29, 1920 with 25.1 degrees in Lucerne
  • March 30, 1989 with 25.2 degrees in Basel

Earliest summer day on the southern side of the Alps:

Latest summer day on the north side of the Alps:

Is it possible that the Sahara dust is ruining our summer days?

The Saharan dust determines how widespread a summer day is. At the weekend a load of Saharan dust will come to us, which can cloud the sunshine. But there is less Sahara dust in the air than last weekend. The air is also drier this time. It is therefore still uncertain how much Saharan dust obscures the sun. If it covers the sun a lot, the temperatures won’t be as high and it won’t be enough for a summer day. But it will still be warm and reach the 25 degree mark in places.

The interview was conducted by Benedikt Widmer.

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