Winters in Siedlce are harsh and cold, with temperatures often dropping below -20°C in January and February. The coldest months are also the darkest, with short days and limited sunlight. As spring approaches, temperatures gradually warm up, reaching averages of 6°C by April and 12°C by May. Summers are mild to warm, with July being the warmest month, averaging around 22°C, while still experiencing occasional hot spells. Autumn is generally cool but not cold, with temperatures dropping back down to around 0°C by September.