What our DL-SHT35 has seen in a cold air pool

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Right now it is summer up there. The mast stands in green pasture, the cows have the place to themselves, and the sensor is measuring the same as everywhere else. In a few months the cold air will start pooling in the hollow again under the right conditions, and the device on the mast will stand above deep snow, exposed to hard frost.

Cold air does not rise. On clear, windless nights it does the opposite: air cooled at the ground grows dense, sinks down the slope and gathers at the lowest point of the terrain. In a closed hollow it has nowhere to go. It pools, and it deepens through the night.

Switzerland's lowest temperatures are not measured on summits. They are measured in dips.

A private research project monitors two of them. At each site, a DL-SHT35-002 records air temperature and relative humidity over LoRaWAN.

In that time both hollows have gone below −37 °C, in the past one of them reached even below -42 °C.

We are not naming the sites. The project's real-time data drew visitors — some arriving in extreme cold without adequate equipment, some camping in protected terrain, some disturbing the measurement field. 

Key facts

Full specs, accuracy, ranges, payload format and more in the datasheet.

→ Download DL-SHT35 datasheet