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In terms of precipitation, rainfall in Helena ranges from 0.3 - 2.1 inches per month. June is typically the wettest month, when rainfall can reach 2.1 in. February is typically the driest time to visit Helena when rainfall is around 0.3 in.
If weather is an important factor for your trip to Helena, 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 69.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 21.2 F).