The Mackay-Whitsunday-Isaac region lies just above the Tropic of Capricorn and has a tropical climate. Summers are generally hot and wet, though the coast has the benefit of a regular afternoon sea breeze. Winter days are generally warm and sunny, while winter nights can be cool away from the coast. 

Mackay's average annual rainfall is 1585mm. A large proportion falls in the months December through to March with the driest months being August and September. Maximum daytime temperatures are typically 29-30 degrees during the summer/wet months and 21-25 degrees during the winter/dry months. 

Minimum overnight temperatures are typically around 23 degrees during the summer/wet months and 13-14 degrees during the winter/dry months. The region lies in the trade wind belt for most of the year resulting in south to southeast winds. During the warmer months afternoon northeast sea breezes are common. Fresh south-easterlies can blow along the coast for lengthy periods during summer and autumn, but gale force winds are rare and normally only occur with a tropical cyclone. The cyclone season is from December through to April with 43 tropical cyclones passing within 150km of Mackay during the years 1910-1992. 

The Pioneer River has a well recorded flood history with records of flooding dated as far back as 1884. Since that time many devastating floods have occurred, with the highest occurring in February 1958 which peaked at a height of 9.14 metres on the Mackay flood warning gauge at the Forgan Bridge.