Planning for the weather is an important factor for making your trip to Compostela a success, especially when you're splurging. The hottest months are usually May and April, with an average temperature of 23°C, while the coldest months are January and February, with an average of 20°C. The rainiest months in Compostela are August, July, September and June, with each month seeing an average of 450 mm of rainfall.