Not NWT, but for all parts of Alaska, uninsulated even through September if active hunting. While I’d expect you could see some cold days, we see snow at elevation during August sheep season, but also see days of flip-flop, shorts-wearin weather.
Think I've made the final decision to just go un-insulated. Expecting lows in 30-40s and highs 45-60s. I'm just thinking any insulation will just be too much.
Last year northern BC had a mid-August blizzard with feet of snow and cold. Unlikely but can happen. I like 400 gram insulated 10" high boots for August and Sept hunts. Take 'em off at lunch and during warm glassing sessions and let them air out in the sun. Works for me...and helps keep the bears out of camp at night.
I live for late season elk in Wyoming, and I don’t even own a pair of insulated boots I would hunt in. I can’t picture how cold it would have to be on a sheep hunt to make me want them.
I wear uninsulated for any active style hunt all year long...that includes coyote hunting in Jan Feb in the dakotas, Mule Deer hunting in MT in Nov. Only time I where insulated boots is in a blind or deer stand if the weather is cold.