The coldest month in Brussels is January where the average low is 35°F and the average high is 42°F. The winter months from November to March are quiet as the crowds have thinned after the Christmas and New Year’s celebrations. Winters are the best times to visit the museums and are perfect for those planning a low-budget trip to the city. And, the best part would be sipping a steaming cup of hot chocolate as snow envelopes the city.