Olsztyn experiences cold winters, with temperatures often dropping below -20°C in January and February. The coldest months average around -3°C, with occasional warmer days reaching up to 16°C. Spring arrives in March, bringing moderate temperatures ranging from -12°C to 20°C, while April and May see a steady warming trend, averaging around 6°C and 12°C respectively. Summer is warm but not hot, with July being the warmest month, averaging around 21°C, before cooling down slightly in August. Autumn brings a return to cooler temperatures, ranging from -3°C to 19°C, with November and December experiencing some of the chilliest days.