Weather is probably a major factor when you plan your trip to Greytown, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and May, with an average temperature of 27°C, while the coldest months are January and February, with an average of 25°C. The rainiest months in Greytown are July, November, June and August, with each month seeing an average of 582 mm of rainfall.