Heather, when I lived in Dillon Mt., Plant out was not until June 8th or so. (Somewhere between June 1st and June 24th). That June 21st frost in 2004 or 2005 I was lucky with. My Tomatoes were on the south side of a large white painted brick building.
My dad went to college in Missoula and he always said Missoula had better growing seasons than Dillon or Twin Bridges. Called it a coastal influence. Maybe a little.
I'm sure glad you're getting things going now!
Ever been to that large nursery in Hamilton? I always forget it's name. Stevenson's maybe?
Glad to hear you got your garden going Heather! I was considering planting mine out on the 18th, but with a hard frost this morning and another predicted for tomorrow, I may hold off another week.