Winters in Nykoping are typically mild, with temperatures ranging from around -11°C in February to just below 6°C in January, averaging around 0°C. Spring brings a gradual warming trend, with March and April temperatures often reaching into the double digits. Summer is warm but not hot, with July being the warmest month at an average of 21°C, while autumn sees a cooling trend, returning to milder winter-like conditions by October.