August is fire season, and under these conditions, the safest campfire is none at all. If you do build a fire (check regulations first), choose your design with safety as a priority. Building a fire on rich, dark organic soils can be dangerous--underground roots can spark up hours later in dry weather. Be sure to wait until morning to fill the pit with the removed soil. This is a good setup for camp cooking. It's not an efficient warming fire, but in August that's probably not your concern.