It was an unusually hot day at the NBCN weather station in Binningen. The minimum temperature was 17.5 °C, the maximum reached 31.6 °C, and the daily mean was 24.0 °C. Since the maximum temperature exceeded 30 °C, the day qualifies as a hot day, also referred to as a heat day.

Looking at the last 30 days, the average air temperature was 22.65 °C, with a minimum of 10.3 °C and a maximum of 38.1 °C. During this period there were 26 summer days, 13 hot days, and 1 tropical night, where the temperature did not fall below 20 °C overnight.

For the current season, the day of interest stands out with a mean temperature rank of 3 compared to all September days on record, meaning it was the third warmest September day by average temperature ever recorded at this station. Its maximum temperature rank for September is 33, placing it well within the upper range but not among the very highest. Compared to the last 365 days, the maximum temperature ranked 46th and the mean temperature ranked 49th.

The hottest September day ever recorded at this station occurred on 6 September 1949, with a maximum of 35.0 °C. The top five hottest September days are listed in Table 1, with values ranging from 35.0 °C down to 34.1 °C. The most recent of these occurred on 3 September 1962. The past day's maximum of 31.6 °C therefore ranks 33rd among all September maximum temperatures in the station's history.