Overnight temperatures in August

[dans]

Hi,
I'm planning on doing a backcountry trip to Glacier some time in mid-August this year and I was wondering what the overnight temperatures are generally like at some of the campgrounds. I saw on the park website that the average lows that time of year are around 45 degrees, but I'm not sure at what altitude that is measured. In particular, would that be the standard low at some of the campgrounds that we were planning on hitting, like Lake Ellen Wilson or Granite Park? Basically I'm wondering whether I could get by with a 40 degree sleeping bag given the weight and size savings (and possibly have to wear clothes inside the bag) vs. bringing a heavier and larger 25 degree bag. Any help would be appreciated. Thanks!

[Ear Mountain]

Temperatures overnight in August are usually warm enough that your 40 degree bag will be OK. But you never know. Snow can fall during any month and prolonged cold rainy spells can happen. I generally carry a warmer goose down bag on my trips. Long johns, a warm shirt, sweater or jacket and a warm hat can help as well.