*3.3. Tmax and Cold Days in the City in the Years 2008/09–2015/16*

In the years 2008/09–2015/16 in the winter season, the average Tmax in the city varied from 2.2 ◦C in Słoneczna to 2.6 ◦C in Collegium Minus and Piekary. In all measurement points, the coolest season occurred in winter 2009/10, and the average Tmax ranged from −0.5 ◦C in Collegium Geographicum to 0.0 ◦C in Collegium Minus (Figure 4). An equally cold winter occurred in 2010/11. The warmest season was observed in winter 2015/16, when the average Tmax varied from 5.0 ◦C in Słoneczna and Strzeszyn to 5.4 ◦C in Collegium Minus, Piekary, and Ławica.

The total number of cold days in the city ranged from 141 days in Piekary and 142 days in Collegium Minus to 160 days in Ławica. The highest number of such days was recorded during the coldest seasons, i.e., in winter 2009/10 (Figure 4). Their number varied from 33 in Collegium Minus to 36 days in Rusa and Collegium Geographicum. Cold days occurred equally frequently in winter 2010/11. They were recorded the most seldom in season 2014/15, when their number varied from 7 to 8 days. In the warmest season, from 8 cold days were recorded in Collegium Minus and Piekary to 11 cold days in Ławica.

**Figure 4.** Average Tmax (black solid line) in the winter season and number of cold days (grey bars) in 2008/09–2015/16 in Pozna ´n.
