High temp for wool?

Wool what? For socks, never.

I wear it longer than I would any other fabric in warm temps… ie, right up to (or after) I'd take any other shirt off… My merino T's feel cooler to me than my cotton ones, for example, or than my silkweight caps…

Used my Smartwool microweight T's all summer here in hot and humid Houston…

Smartwool (and I assume, albeit without experience – Icebreaker) works well in hot & humid Florida.

The 150 tee is my hot weather layer , but I noticed at White Blaze that Earthing reports getting prickly heat ( Miliaria) from it.
http://en.wikipedia.org/wiki/Miliaria
I don't sweat very much and have no reactions whatsoever from wool (even the raw stuff) so that could make the difference.
But maybe it is because Earthling is an Aussie , they are a strange mob.
Franco
By wool, I mean IceBreaker.

For socks and boxer-briefs, it's year-round. For tops, when highs are above 50F, the wool stays home. Below 50, wool is sort of comfortable for me 'til the 30s, and below that I can't feel the itch much (talkin' Smartwool and Patagonia wool). Definitely a winter fabric for me. Patch-soaked wool from perspiration ain't no fun as it takes a looooong time to dry, but the evaporative cooling of synths ain't much fun either (but I trust it will dry from body heat in a reasonable time.

Socks never. Lightweight bottoms, like 40s to 50s. Lightweight tops up to 80 if there is some wind.

I've never used the microweight stuff. I'd expect a microweight tee to be fine in anything but I've been rocking white long sleeve cap 1 stuff when it's super sunny and hot. Hoping to try the lighter colored wool 1 stuff when I can find a bargin.

For me wool equals winter. Tried it as a baselayer for spring backpacking, but found it to hot. So I'd say daytime temperatures in the fifties is about max for me. YMMV.

My Icebreaker tee works all summer here in the hot and humid Southeast.

I'm going to also give wool the any time nod! Perfect for winter or summer.

I have had no problems with it drying. I once rolled my shoe into a very cold creek on a chilly, 80 percent humidity morning. I took off my 200 weight Icebreaker, crammed it into my shoe, put on my rain jacket, cooked breakfast, and did various "while stopped by water" chores. When all was done, my shoe was considerably drier and my shirt was dry after about twenty minutes of hiking.

Jack

I have noticed that when I start to use wool above 70F it starts to get itchy and I don't really know why as I am fine below that. Any ideas?

And that is with tops, with sock and underwear I can go higher.

I wear my Icebreaker Tech T Lite all summer here in the hot South…no problems. I wouldn't have believed it until I tried it.

Wool regulates body temperature better than any other material known to man. Hot or cold weather. Its the perfect base layer.

Keeps you warm in the winter, cool in the summer. Much cooler and cleaner than sunscreen. For summer, like the wool to drape ever so slightly as opposed to skin tight for winter. Doesn't chill when wet like Patagonia Cap 1 (which I like for a quick run when I can get out of it right away!) My fave for summer: Icebreaker Mako Zip. Full coverage. Think they stopped making it but sure to be many similar items in 150ish wool.
Summer in SoCal.

I don't wear much in the way of wool here in SE Arizona during summer. In the desert, from late-May through September, temperatures can be over 110°F. Mostly, I wear a light-colored cotton LS shirt and a broad-brimmed hat. Most folks who spend much time outdoors here in summer do the same. I suppose that one could wear wool, but why?

I think the Bedouin know what they are doing by using wool for their garments in the Sahara. It is the material of choice for them. Same with the nomads of the Gobi Desert.

Very thin merino wool like Icebreaker 150 does great in high temperatures, even humid, 45º C temperatures like here in Japan in summer. Cools just like a cotton t-shirt, , handles the temperature variations better, and doesn't have a pong. Cotton t-shirts would be great if they could also be warm when wet and cold. Wool is.

I wore wool at 114F in Death Valley a few months ago. It was 114 at Furnace Creek. I won't say I felt good wearing it because I was sweating bullets with or without the shirt. I also dipped my cotton T in Cold water and just wore that and that felt far better. So in that situation I did stop wearing wool since wet merino doesnt make your body feel the moisture anywhere as close as Cotton does. My $0.02