Planning for the weather is a good way to make your trip to Santa María Huatulco relaxing and enjoyable, especially when you're splurging. The hottest months are usually April and March, with an average temperature of 26°C, while the coldest months are January and February, with an average of 25°C. The rainiest months in Santa María Huatulco are September, June, August and October, with each month seeing an average of 505 mm of rainfall.