Planning for the weather is an important factor for making your trip to Arcos de Valdevez a success, especially when you’re splurging. The hottest months are usually August and July with an average temp of 67°F, while the coldest months are February and January with an average of 50°F. The rainiest months in Arcos de Valdevez are October, December, November, and January, with each month seeing an average of 9 inches of rainfall.