3.4.1. Tmax in the Heat Waves

The heatwave lasted from 8–17 July 2010. On 8 July, it started in Collegium Minus and Piekary, while for the rest of the area it was on 9 July. Mean Tmax during the wave ranged from 32.5 ◦C in Collegium Geographicum and Ławica to 33.7 ◦C in D˛ebina. At most points, the highest Tmax was found on 12 July and fluctuated from 33.1 ◦C at Słoneczna to 35.4 ◦C in Collegium Minus (Figure 5a). During the heat wave there was a marked cooling on 14 July, caused by the passage of a warm weather front. Then Tmax changed from 30.1 ◦C at Słoneczna to 32.9 ◦C in Collegium Minus.

In 2015, the start and end of the heatwave varied across the city. At six points, it began on 2 August, while at three points it only started on 6 August. The end of the heat wave was recorded between 15 and 18 August. The mean Tmax during the wave ranged from 31.9 ◦C in Ławica to 32.8 ◦C in D ˛ebina. At all points the highest Tmax was recorded on August 8th, which ranged from 36.8 ◦C at Słoneczna to 38.3 ◦C in Swierczewo (Figure ´ 5b).

**Figure 5.** Tmax during the heat wave of 8–17 July 2010 (**a**) and 2–18 August 2015 (**b**).
