Chelm's winters are cold and variable, with temperatures often dropping below -20°C in January and February. As spring approaches, temperatures gradually rise, reaching averages around 7-13°C in April and May. Summer brings warm days, with highs sometimes reaching up to 34°C in June and July, but nights can still be cool. Autumn is mild, with temperatures ranging from 2-20°C in September and October, before dropping again in November and December. Overall, Chelm's climate is characterized by moderate temperature fluctuations throughout the year.