3.4.2. Daily air temperature on 9 February 2010 and 21 February 2011

On 9 February, the daily course of air temperature throughout the city was approximate (Figure 6a). The lowest air temperature was observed at 6–7:30 UTC, and the highest at 12–14:30 UTC. Minimum temperature in Pozna ´n ranged from −15.8 ◦C in Collegium Geographicum to −11.1 ◦C in Słoneczna, and maximum from −5.2 ◦C in Collegium Geographicum and Słoneczna to −3.3 ◦C in Collegium Minus. During the day, differences in air temperature between particular measurement points were considerably lower than in night-morning hours. The smallest differences (approximately 1.1 ◦C) occurred around midnight, and the highest in morning hours with a maximum at 6:30 UTC (5.0 ◦C). During the analyzed day, air temperature amplitude varied from 5.9 ◦C in Słoneczna to 11.0 ◦C in Strzeszyn.

On 21 February 2011, similarly as on 9 February 2010, the daily course of air temperature was approximate in all measurement points (Figure 6b). The lowest temperature was observed at 6:30–7:30 UTC, and the highest at 12–13:30 UTC. Minimum temperature ranged from −16.7 ◦C in Ławica to −14.6 ◦C in Piekary, and maximum from −8.2 ◦C in Collegium Geographicum to −5.6 ◦C in Collegium Minus. The smallest differences in air temperature between particular points were observed in morning hours with the minimum at 8:30 UTC (1.1 ◦C), and the highest in evening hours with a maximum at 19 UTC (4.3 ◦C). The daily air temperature amplitude in particular points ranged from 7.5 ◦C in Słoneczna to 9.3 ◦C in Collegium Minus.

**Figure 6.** Daily course of air temperature in Pozna ´n on 9 February 2010 (**a**) and 21 February 2011 (**b**).
