Winters in Sandefjord, Norway are harsh and cold, with temperatures often dropping below -20°C in January and February. The spring season brings a gradual warming trend, with March temperatures fluctuating between -9°C and 18°C before stabilizing around 5°C by April. May marks the beginning of warmer months, with average highs reaching 28°C, while June and July are characterized by mild temperatures ranging from 4°C to 30°C. Autumn is generally cooler, with September experiencing a slight drop in temperature compared to August, before October's averages rise again, similar to those seen in May. December returns to winter-like conditions, with temperatures fluctuating between -15°C and 10°C, averaging around 3°C.