The temperature of the environment affects how, and how long, a fragrance wears. Heat energizes the chemical reactions that release fragrance, resulting in a stronger scent. In warm weather, you'll need a lighter application, or a less concentrated form, of whatever scent you wear.
At the same time, heat speeds evaporation. If you go with lighter scents, you'll need to reapply them more often in warm weather, due to their low concentrations. As an aside, be careful of what you wear outdoors. Certain unwanted creatures may share your taste in fragrance. Bees are attracted by sweet, floral scents. Beetles prefer spicy ones. Bats are partial to musky notes. Something to keep in mind if you're heading to a backyard barbecue.
The same principle applies in reverse in cool weather. Chemical reactions are more sluggish at lower temperatures. Fragrances emanate gradually, with less intensity. If you're wearing a warming winter scent, however, consider the heartiness of the bottom notes. Adding an extra spritz could give you the ambiance of a human pine forest.