Guerrero Negro: are you wondering about the weather you might find during your holiday? Befor organizing a holiday we always think about the wheather we might find when we get there. In Guerrero Negro the average yearly temperature is 24°C. During the hottest month, which in this case is August, the temperature can get up to 29°C and the temperature of the sea reaches 23°C. Instead the coldest month is January, reaching a minimum temperature of 20°C. Here instead the water temperature drops to 16°C.