Hot day
Temperature & humidity Day with at least 30 °C
In German weather statistics, a hot day reaches at least 30 °C air temperature. The threshold applies to a shielded measurement, not a thermometer in direct sunshine.
Counting starts at thirty
The meteorological threshold is a daily maximum of at least 30.0 °C. A brief exceedance is enough. A thermometer on a sunny wall is not directly suitable: sunshine and the wall heat the instrument as well as the air.
A hot day is also a summer day
Summer days begin at 25 °C, so every hot day is already included in the summer-day count. Adding the two figures would count the hottest days twice.
Comparing annual counts
The number of hot days varies from year to year. A climate average combines many years and always belongs to a location and reference period. The frequency alone also does not tell you how well a home cools down at night.
A statistical threshold, not a personal limit
Humid conditions at 29 °C may feel more demanding than 30 °C in other circumstances. Hot nights, activity and lack of shade matter too. “Not yet a hot day” is a statistical statement, not an all-clear for heat exposure.
In Hanover
How many does Hannover have?
The DWD station Hannover averaged 7.7 hot days per year over 1991–2020. July averaged 3.3 and August 2.9. Decimal values arise from the long-term average; an actual qualifying day counts as a whole day.