Michael L wrote an answer about Big Agnes Flying Diamond 8 Tent: 8-Person 4-Season on May 25, 2011
I agree with you Mike Miller,that it's not a hardcore 4 season tent. I wouldn't want to depend on it like my North Face VE-25 (which has been used in expeditions in the Artic and Antartica), but the Flying Diamond will hold up very well, and hold in heat, in the unexpected snow/sleet/hail storms that I've faced in Tuolumne Meadows in Yosemite (that was a nightime, 6 inch snow storm over a Memorial Day weekend), or the snow/sleet/hail storm I faced in Yellowstone last August (photo attached), or the snow storm/blizzard on the North Rim of the Grand Canyon year before last in early Oct., at 8,300'. Structurally it'll hold up, but there's too much uncoverable mesh in the tent to hold in body heat at temperatures below 10 degrees F., but I can attest that it's done very well at 25 degrees. I haven't tried it at temps near 10 degrees F yet (and I don't intend to), so that part is just my opinion.