Planning for the weather is a good way to make your trip to Blumenau relaxing and enjoyable, especially when you’re splurging. The hottest months are usually January and February, with an average temperature of 23°C, while the coldest months are July and June, with an average of 16°C. The rainiest months in Blumenau are January, February, March and December, with each month seeing an average of 213 mm of rainfall.