Don't assume a trail or lake is thawed out, and don't bet your trip on second-hand information. Check with the ranger station before you go. At the same time, remember it gets hot on open, sunny slopes, and the creeks are drying up. Carry plenty of water and get an early start. Carry extra water for your dog, and be advised that the Forest Service is becoming intolerant of unleashed dogs on trails.
Bugs love the heat, so be prepared with potent repellent.
Check for ticks daily. Fire hazards are high all over the Northwest. What we've been seeing on the news from the southwest could happen here. Use your ashtray. Drown your campfire, or reconsider whether you really need one, when it's light and warm all evening.