First set the mood:
You can see aurora borealis any time of year in Glacier National Park, but spring and fall, when the nights are a bit longer and darker, is prime time to catch an incredible light show in the sky.The foot of Lake McDonald, near Apgar, is a great spot to watch for northern lights in the spring. There are apps you can download and websites (like this one) that will tell you when conditions are good for aurora. If you want to catch the show, find a spot with no light pollution and a low northern horizon. Having a clear view and low horizon to the north significantly increases your chances of seeing aurora at our latitude.