What can the Groom wear for a summer wedding?

We're getting married in February in Brisbane and it's very likely to be hot and sticky. Now, I want my fiance to look sharp, but I don't want him to suffer either. What do you suggest he wear? (Don't worry about best man or groomsmen, we're not having any.) It's a garden ceremony in the shade, and the bride is wearing a simple tea-length dress, if that makes a difference.