Other facts from our historical weather data: When is summer in Belle Fourche?The hottest season / summer takes place in June, July, August and September. Does Belle Fourche have a dry season? Yes, the months of January, February, November and December are very dry. Which is the warmest month in Belle Fourche? July has an average maximum temperature of 31°C (88°F) and is the warmest month of the year. Which is the coldest month in Belle Fourche? The coldest month is December with an average maximum temperature of 2°C (36°F). Which is the wettest month in Belle Fourche? May tops the wettest month list with 91mm (3.6 in) of rainfall. Which is the driest month in Belle Fourche? January is the driest month with 9mm (0.4 in) of precipitation. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.