I don't know about you, but I knit all year long.
First off, I just can't stop knitting….
What works for me is to choose yarns that either are fine like a sport or sock weight or feel cool to the touch, such as linens or cottons.
Also bigger needle do work well as they open up the fabric, make it feel a bit more on the loose side and can even create somewhat of a lacy feel. Your projects also drape well when knitted on larger needles.
You can see some of my newest projects for the summer in the link below: