I'm sure you can relate to this - seriously who likes to iron their clothes?!? We all love those pieces that just wash, dry, wear again. We tend to wear them more often, which justify the investment.
Unfortunately there is a trade off between the need to press and how cooling a garment is. 100% cotton is usually more cooling but can be a nightmare when it comes to pressing. Striking a good balance is key. Choose cotton-blend (usually a mix of cotton and another material such as polyester) for comfort on a warm day out. It is generally easier to press than 100% cotton, even my steamer can handle it. And if your washer has a speed control, go for a lower RPM, give the washed garment a few good swings and hang it up to air-dry. I usually get away without pressing this way (unless you are the super-fussy type).
These are some of our latest cotton-blend plain tops for your outdoor events:
Rayon is another good option to stay cool. It resembles your ordinary T shirt, and usually contains some spandex. Unless you like your outfits very fitted, I tend to go for one-size bigger when I choose rayon outfits so that they are not too clingy. Rayon feels comfy like your home-wear Tshirts but it's important to style them up with a statement necklace so they do not appear too casual.
Refer to these Koordinated looks for ideas: