Weather is probably a major factor when you plan your trip to Sherrard Island, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually October and November with an average temp of 82°F, while the coldest months are August and July with an average of 77°F. The rainiest months in Sherrard Island are January, February, March, and December, with each month seeing an average of 14 inches of rainfall.