Get the EDT instead of the EDP
EDT, or eau de toilette, is less concentrated than EDP, or eau de parfum. As a result, EDTs tend to be lighter and have less sillage (aka a scent trail).
Wear it outside
The problem with trying something on in a store where the air conditioning is on full blast is that it holds the perfume in place. Perfume oils react with heat to release their aromas, so to get a sense of how your perfume is really going to smell, spritz a bunch on and then go stand outside. If, after a day of walking around, doing errands, crossing hot parking lots, etc., you still like it, then it's a go.
Look for citrus notes and woody or grassy bases
This doesn't always hold true, but it's good as a rule of thumb. Fragrances with tons of citrus notes (think mandarin, lemon, lime, etc.) are usually light, since citrus smells are so airy. With woody bases like sandalwood, blond woods, or grassy bases like petit grain, they aren't robust enough to anchor most cold-weather scents, so you're likely to find them in Summer-ready concoctions.
Try a single-note scent
Most scents develop significantly over the course of a wear, but hot weather can speed that process up too much, leading to unpleasant note combinations or fragrance that barely lasts a few minutes. Single-note scents like lavender, vanilla, ylang ylang, and jasmine have more staying power, and you know exactly what you're getting with their scents.
Switch to solid perfume
If you're tired of having scents disappear off your skin in the heat, maybe it's time for you to try wearing your scent in a different medium. Solid perfumes are more subtle than their alcohol-based counterparts, but they also last a long time on skin since the unguent base holds onto essential oils.
Ask a friend
Sometimes, the problem with a scent isn't your nostrils — it's everyone else's. Before you buy, walk around outside for a while and then ask a friend whether your perfume is strong. It can save everyone a lot of (literal) headaches later.
Source: Flickr User jonycunha