Fig. 2

Temperatures recorded by microclimatic data loggers at selected study sites south (a, c and e) and north (b, d and f) of the Alps in January 2017: daily mean temperature (a and b), daily temperature range (c and d) and daily minimum temperature (e and f). The letters I and E following the study site’s name indicate whether the temperature was measured inside catch basins or as external control, respectively. The box plots represent median (solid lines within boxes), mean (x marks within boxes), 25th and 75th percentiles (boxes) and minimum and maximum values (whiskers). *Significant differences between groups. Abbreviation: NS, not significant