How do I keep perfumes from getting damaged in summer?

Keep them cool and dark, away from direct sunlight and heat. The ideal spot is a shelf in a room that doesn't get sun, or inside a closet. If you really don't have cool spaces, a bedroom drawer works fine. The important thing is to avoid bathrooms, kitchens, and south-facing windows - heat and humidity damage the fragrant molecules and change the scent pretty quickly.

Check the temperature: in summer it should ideally stay between 15 and 20 degrees. If the perfume is in a dark bottle or tinted glass, it's already better protected than transparent bottles. Some have an integrated spray cap that seals well; others don't. If you notice the perfume's top is loose, tighten it before storing.

An extra tip: put the bottles inside an opaque box or non-transparent cloth bag, and if you have a particularly cool corner of your house (like the back of a closet that's not exposed), even better. If you live in an air-conditioned area, that's the perfect spot. Don't put them in the fridge unless you have dedicated, controlled space - the fridge's humidity can damage them anyway.