Planning for the weather is an important factor for making your trip to Oliveira do Castelo a success, especially when you're splurging. The hottest months are usually August and July, with an average temperature of 20°C, while the coldest months are January and February, with an average of 9°C. The rainiest months in Oliveira do Castelo are October, December, January and November, with each month seeing an average of 241 mm of rainfall.