oslo weather year
Oslo: Annual Weather Averages. July is the hottest month in Oslo with an average temperature of 18Â°C (64Â°F) and the coldest is January at -3Â°C (27Â°F) with the most daily sunshine hours at 14 in July.The wettest month is August with an average of 90mm of rain.Loading weather data.uly is the hottest month in Oslo with an average temperature of 18Â°C (64Â°F) and the coldest is January at -3Â°C (27Â°F) with the most daily sunshine hours at 14 in July. The wettest month is August with an average of 90mm of rain. Loading weather data.