In terms of precipitation, rainfall in Brittany ranges from 1.5 - 3.0 inches per month. October is typically the wettest month, when rainfall can reach 3.0 in. August is typically the driest time to visit Brittany when rainfall is around 1.5 in.
If weather is an important factor for your trip to Brittany, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 66.2 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 42.8 F).