Black/Brown spots have appeared (overnight). Girls seemed great up to this point. First outdoor grow!

Hi fellow grower, as you've mentioned on your question you are having issues with humidity at night. This will be causing the roundness of your leaves. The dark spots look like oxygen starvation in the root zone. Could be a couple of things, water too cold can starve a plant of oxygen. too hot and nutrients are harder to absorb. Best way to get oxygen back into your roots is to use 3% hydrogen peroxide/water mix and add to your soil. Not sure of ratio so something to check up on! This will infuse oxygen into your roots. Keeping the water between 65-70'F will allow your plants to absorb all the nutrients and oxygen it needs. Otherwise your plants look great. Keep up the good work 🙏