Planning for the weather is a good way to make your trip to Mertak relaxing and enjoyable, especially when you’re splurging. The hottest months are usually October and November with an average temp of 81°F, while the coldest months are August and July with an average of 79°F. The rainiest months in Mertak are December, January, February, and November, with each month seeing an average of 11 inches of rainfall.