Only the month of February has averaged minus degrees -0.8 degrees celsiusi period 1931-1960. The thermometer showed 0.7 in January, - 0.8 in February, 0.7 in March, 3.8 in April, 7.4 in May, 10.4 in June, 13.8 in July, 13.5 in August , 10.6 in September, 6.5 in October, 3.3 in November, 1.3 in December. In the period 1961-1990, there are three months of average sub-zero temperatures: -0.1 in December, -1.1 in januarog -0.6 in February. As the preceding 30-year period is July and August the hottest with 13.1 and 13.0 degrees Celsius.
On the basis of available weather statistics have Brønnøysund a yearly average of 5.8 degrees in the period 1931-1960, while 1961-1990 is the standard temperature of 5.6 degrees.
Empirical May is the month that has at least rain, while October has three times as much. "Normal rainfall in mm, for months 1931-1960" shows the following figures for Brønnøysund: 115 in January, 108 in February, 117 in March, 87 in April, 66 in May, 90 in June, 103 in July, 99 in August, 143 In September, 186 in October, 107 in November, 123 in December. In the period 1961-1990 is still in May that at least precipitation (66 mm) and October, most (192 mm).
Brønnøysund has an average rainfall of 1345 mm each. years in the period 1931-1960, while the rainfall for 1961-1990 is 1510 mm per. year.
Wind conditions vary with the season. In November, December, January, February and March is the main east wind in Brønnøysund. This is often a weak wind or gentle breeze. The strongest winds are usually from the sector south to north. In May, June, July and August are the main north direction with often a light breeze. This often provide clear weather, but increases the need for wind screen to enjoy the sun. Also wind from the east often provide good weather in Brønnøysund. April is a transition month with two equally frequent wind directions, north and east. September and October have often wind from all directions, but rare north wind. (Builds on three daily wind observations 1956-1965).
These primary images of climate in Brønnøysund For some parts of the municipality be changed by the local topography and location, and therefore can show large differences. We see this in Velfjord area where it is more inland climate, with colder winter and warmer summer. When we get even further into the country, east to the neighboring municipality of Grane, we usually snowy winter. We have much else to thank the Gulf Stream underwater "blood circulation" for.