In terms of precipitation, rainfall in Gillette ranges from 0.4 - 2.5 inches per month. May is typically the wettest month, when rainfall can reach 2.5 in. January is typically the driest time to visit Gillette when rainfall is around 0.4 in.
If weather is an important factor for your trip to Gillette, 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 71.6 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 24.8 F).