laskatx, hubby is a runner and has run in many different temps. He also umpires sometimes in cold weather early in spring. I told him your son's situation and he said the best bet would be regular UnderArmor leggings, not too tight, and not what's meant for the cold temps. The later would be too warm in class.

I would probably try silk. That's what I wore when I used to commute in cold weather but then work in a warm office

I agree. Thanks. I will check out the UnderArmour -- those might even be available here in sporting goods stores. I also found a silk interlock knit at Land's End that comes in talls (DSs are both right at the borderline for needing talls -- 6"3"-6'4") and several comments said they were warm outdoors but lightweight and not too warm indoors. I think either would be beter than the occasionally found cotton or cotton/poly waffle knit here. Forwarding him both possibilities. Thanks again -- and I will check back to see if there are more comments.

Hhireno, know what else is funny about this place? Your coment spawned a new comment alert in my email, but neither of the other posts have -- at least so far.

Woops -- crl_ is now there......

We swear by midweight UnderArmour for skiing. I believe they have numerical classifications for weight/warmth. They are not inexpensive but a great product.

This may help:

http://www.evo.com/how-to-choose-ski-base-layers-long-underwear.aspx

Hhireno, you know what's funny? Not for this topic, but the one about flying in that airline, I asked my dh about it b/c he works in travel risk management. He'd heard of the airline but was going to check out their company info for me later when he logs onto his laptop. So, yes, this place is a great resource for gathering information and opinions!

as for the OP's question, I like silk long underwear b/c it is very thin but agree it might make him too hot indoors. I do have many UA leggings but for me personally I wouldn't feel comfortable wearing them under dress pants but that's just personal preference. Just a little too "thick" for lack of a better word and cause my pants not to fit correctly. He might have better luck though.

My brother lives somewhere near you - in Spring - and if he has to come up north to visit family in the winter he also wears UnderArmour.....and then complains while staying with me that my house is too cold for his Texan blood.

Which is really funny since we all grew up in Pittsburgh and spent the winters sledding and ice skating and never worried about the weather. I will admit though that it could get numbingly cold sitting at a Steeler game - and this was before we had the benefit of hi-tech clothing.

I hope your son is enjoying his stay. And be aware - it's going to get colder - occasionally the rivers freeze. But the worst part is the ice on those hilly streets - just a few days ago they had a clip on the news here in Philly showing cars sliding down an icy street in Pgh and smashing into each other at the bottom. Luckily Oakland isn't too bad but other areas of the city have really steep streets.

http://www.wtae.com/image/view/-/31392088/medRes/2/-/maxh/630/maxw/1200/-/402nea/-/frozen-Allegheny-River.jpg

Both my boys are tall and they both wear Under Armour. Both are out right now (one is out doing a winter hike to see the sunset and given that it's about -5C is wearing his warm gear although probably not quite as cold where your son is) and the other one works for an outdoor clothing gear outfit. When they get back I will ask what type of material they suggest.

For cold weather running I wear polartec or a nylon running shirt with polartec on top, but look for something that will be "wick-away".

Dressing in layers will be the best thing for him, wearing a toque when he's outside (lose most of your body heat from the head) and then taking it off when he's inside and a pair of light hikers with wool socks.

Ditto UA products, especially for wind-resistance and warmth. I wouldn't get silk if you are looking for something to be warm in wind. It would be great for all-day wear, but for an all-day multi-purpose warmth, get UnderArmor. The only other choice possibility would be a mid-range Patagonia Capilene.

I am in Alabama but run in the cold and ski and will wear my lightweight Capilene under a cashmere pullover sometimes. It's chilly in my office.

I love Cuddleduds. Often I wear them under my scrubs in the winter. Sometimes I sleep in them. http://www.amazon.com/Cuddl-Duds-Thermal-underwear-layering/dp/B00EUE1N5I

My DH is tall, thin, and cold-blooded, and he loves Capilene. He wears the lightest weight under dress pants/jeans during the winter, and the heavy weight for outdoor activities. It's very thin, breathable, and not at all bulky.

http://www.rei.com/product/884935/patagonia-capilene-lightweight-long-underwear-bottoms-mens

I have worn and loved WinterSilks for many years! they're all silk and come in three different weights. Just went to get the link for you and see they're 30% off today. Men's WinterSilks

This is too funny...I grew up in Spring....I am a native Houstonian.

I have some that I got at a sporting goods store...Dick's, I think, but Sports Authority and maybe Academy should have them.....

they came in a plastic tube, and could be. Champion or Under Armour....but they are very thin, and metallic on the inside to reflect your body heat back inside. Wonderful!!

I haven't read any of the replies and I'm sure someone must have suggested Wintersilks. We all have them and they are really warm. I wear the lightest possible version (they come in various thicknesses) as it adds very little bulk under one's clothing.

Patagonia Capilene is the standard around here. There are different weights, taking you from "California cool" (as a field biologist, I often wear these, in "light" or "silk" weight, as an underlayer in winter) to heavy, expedition-grade stuff meant for Mt. Everest and the like. Not cheap, but I have some pieces that are close to 20 years old and still in use!

Thanks everyone. Lots of options to check out. After I wrote the question, I remembered that he only had a jacket in NYC, but he does have an overcoat he left in his apt over the break. If it is windy, he could wear the overcoat to and from campus and take it off. That may prove to be the easiest solution (wouldn't it?), but I do think it would be good to have a couple of options and I don't know what he bought in NYC. I'll do some more research and send him some ideas.

Springroz and Marie_cate, I grew up in Spring -- at least 5th grade through HS, and now live a little further north. DS is at CMU and his apt is in Oakland -- on the edge near Shadyside. Maybe I've shared that before -- he seems to be happy with where he is on both counts, and he just had a great visit in NYC.

I have a Facebook friend who recently took up bicycle riding. She didn't want to stop once the weather got colder so she went shopping for long underwear. She found a pair she liked but as she was passing the men's section she noticed their long underwear was several dollars cheaper. so she bought a pair of mens long underwear and she is thrilled that they come with a little pocket on the front just below the waist to hold her cell phone. She's a hoot.

I also wear Cuddl Duds......every day of the winter. I get the stretchy kind. They are very lightweight yet keep out the air. I wear them while I am inside and when I am outside walking. They are perfect .

Your son at CMU will still have a lot of cold weather yet to come. I hope that he is enjoying his time in the Steel City!

Chicago, here where the temp today was 0.

I think I have tried every brand of long underwear. UnderArmor are great, high quality, but sometimes a bit too warm inside. Probably my favorite brand that are not too warm indoors are LandsEnd silk.

The theory of losing more heat through your head has been debunked. That doesn't mean you shouldn't wear a hat for warmth.

I have two silk, Lands End tank style undershirts. I bought medium and they're a little big. I didn't have the time to return and try another size, before I needed to pack them for a trip, so I kept them. So if anyone orders them from LE, the sizing is generous in the tand style undershirts. They wash and wear well.

Trying some from Land's End and some from Wintersilks since they have talls and a fly -- which some did not. DS had car trouble last night on the way to an off camus class and had to go back to get the car towed this morning. First driver left without calling him and he had to wait nearly 2 hours. Kind of underscored the need for some longjohns. LOL Hate it when your kids have problems, but so glad nothing was worse.

Where did you go to school? When?