Planning for the weather is an important factor for making your trip to Whitsundays a success, especially when you’re splurging. The hottest months are usually February and January, with an average temperature of 27°C, while the coldest months are July and August, with an average of 21°C. The rainiest months in Whitsundays are March, January, February and December, with each month seeing an average of 278 mm of rainfall.