Crater lake

Mosquitoes are all but gone by the end of August. If you can stay near the lake then you won't notice them. They don't like wind. Several years ago we camped at Broken Arrow CG which is a very short distance from the lake. 100's of skeeters. Down at the lake almost none. Too windy. That was in July too. Sept will be perfect. Weather should be great. Crowds thinner. Make sure you do the Rim drive. If you're into hiking there's some really nice short day hikes. Another nice trip is the boat ride on the lake. It's a good hike down to the lake but really worth it. You can't see many of the lakes features from the rim.