What weight icebreaker baselayer for year round use?

I, personally, find that 190 works fine as a spring/fall base layer, but I definitely go to 150 in the summer. So, I guess I wouldn't be happy with just one or the other.

Append my post since I forgot to add that my 190 is long sleeved which is part my reason for switching to the 150 in summer. I prefer the bodyfit style of the 150 and 190.

One Icebreaker? How could that be? :-)

I have every weight made from 140 short sleeve tee to 320 hoody. I even have an Ibex 390 weight. Seriously!

Except for mid-summer when just the 140 is all I need, I pull out two different weights. That way I can have 3 different temperature settings by wearing only the lighter one or only the heavier one or both combined.

My only other torso garments are a windshirt for 3 season and add a puffy hooded jacket for winter. A poncho serves as raingear for fall, winter and spring. In summer I get wet.

Ha no not just one icebreaker. I'll be ordering various midlayers weights, but for a baselayer I wanted just a couple. Really, I'm wondering if there is much of a difference in comfort between 150 and 200; both are listed as year round use.

If I had to choose one it would the 190 weight. I have used a 190 t-shirt for a year of around town use and it still looks brand new. It is more durable than the 140 weight but still does well in hot weather. The 190 and 140 weights are more comfortable to wear than the 150/200 weights because they have a looser fit.

The 200 is itchier than 140, 150 or 190.

Really? I tried on a 190 Tshirt and it fit like a regular Tshirt would. The 150 and 200 are bodyfit baselayers, known for their tight fits.

I wear an Ibex Outback which is a 150 weight and find it perfect for all but the more extreme summer temps.

I use Patagonia wool 2, which is same weight as Icebreaker 150. Perfect for summer trips or cross-country skiing. Personally I always get the long-sleeve zip-T; shove up the arms and drop the zipper if it gets hot, pull down and zip up at rest stops. Patagonia's wool 3, ~230g/m2, has worked really well for me year-round, too, but the lighter weight is a bit more versatile. Even when I drench the wool 2 w/sweat, body heat drys it out in about 20 minutes after the pack comes off. For less active times, the 200 would probably be better; a touch warmer, but still regulates temperature quite well enough to handle most other stuff…