Stay in Linen.
Linen is a lightweight fabric with a very breathable consistency. Opt for flowing styles that don't cling to the body, and lighter tones. Great for a casual date night where one might be going to an indoor restaurant, then outside afterward. Another great fabric to stay cool with is a lightweight 100% cotton, denim. The denim shirt or short is a great vintage flashback trend that is great for hot summer days when you're tired of the T-shirt.
Skirt Around the Issue.
Ladies! You have the option not to wear trousers! Try a lightweight skirt that flows in an outward motion to stay cool.
Play Dress Up.
70's length maxi dresses are really popular right now, pick your favorite style and try accessorizing with big chunky wooden bangles, and a pair of flat sandals to stay comfortably stylish.
Avoid Pits of Despair
If you're at an outdoor summer social function outside, chances are you'll see a lot of, um, pit stains. Yikes! Gross! That's right, I said it. Ew.
If appropriate, opt for a top that breathes easily, hangs looser around the body, and if you can, is sleeveless! If you're heading to a wedding that requires the shoulders to be covered while inside, just wear a light jacket or cardigan, then when the outdoor reception starts, party on(without it).
If you tend to sweat on your lower half, try this trick: It seems like the opposite of what you've probably heard, but a darker color with a print in a flowing fabric will hide some of those embarrassing sweat marks.