July is the hottest month in Bordeaux with an average temperature of 21°C (69°F) and the coldest is January at 6°C (43°F) with the most daily sunshine hours at 8 in July. The wettest month is January with an average of 110mm of rain.uly is the hottest month in Bordeaux with an average temperature of 21°C (69°F) and the coldest is January at 6°C (43°F) with the most daily sunshine hours at 8 in July. The wettest month is January with an average of 110mm of rain.