As a note in the Thingy:53 user guide, it is stated "The Nordic Thingy:53 shall not be operated outside the internal battery’s discharge temperature range between –20°C and +60°C or stored or transported outside the internal battery’s storage temperature range between –20°C and +30°C." Humidity rating is not done for the Thingy:53, but the internal battery used has a humidity rating of 65 +-20% RH. I don't think any of the other components would have a stricter humidity rating. If you want to check, the HW files and full BOM for the Thingy:53 is downloadable here.
