Wool Base Layer 35F-60F Comfort while hiking?

200 weight is considered lightweight and Icebreaker has a few to choose from. Try Minus33 also has a few styles

http://www.icebreaker.com/en/mens?prefn1=fabricWeight&prefn2=productType&prefv2=Base%20Layers&prefv1=150%20-%20160%20Ultralight

I like the lighter ones for base layers for "summer" temps- 150 or less; (for winter I've been using an Indie hoody that works really well)

Ibex makes a 150 zip, I have one- it's a nice base layer; the other one I wear a lot is Patagonia's Merino 1- it's a crew though, but very light and a little better at drying quicker as it has a mix of capilene in it

I find in those temps that I wish my cap 1 was thinner. But temps here are always in that range. I wear a nylon button up shirt, or a syn, short sleeve. Luckily for me my funk factor is low.

Ibex's 17.5 Nelson has the widest temperature comfort range for me. I can wear it almost into the 70's, yet it's still warm enough for the high 30's with exertion.

The loose fit and the non-itchy weave do it for me. Also the best cuffs I've seen on a wool shirt. Relatively high collar for a crew neck.

At those temperatures I like to wear my Hooded Indie. Between the 1/4 zip, hood and pushing up the sleeves I can adjust it until I'm comfortable. If the wind gets to be a bit much it layers well with my windshirt.

Stoic Alpine Merino 150 Bliss Shirt – Long Sleeve – Men’s sale $37.95 – $69.00 depending on size and color, Icebreaker Aero Long Sleeve Half Zip 120 Featherweight is $84.99, the Sphere Long Sleeve Hood is 135 Featherweight but no zipper, Relay Long Sleeve Half Zip 150 Ultralight on sale for $59.99 and Sonic Long Sleeve Half Zip 150 Ultralight

If only merino were able to be woven with higher sun protection factor it would be the best all around fabric. (I guess durability could be increased too.)

I have a BPL wool hoodie that I have used in the following temperature range 30's to 90's and was very comfortable. I think the wool weight was lower than the Ibex Indie Hoodie.
It is too bad they stopped making them. At one point I had 2 of them but foolishly sold one

You might want to look at First Lite's Llano QZ. It's a quarter zip for additional ventilation in hotter temps, 170 weight, long sleeve.

I really like my Mountain Hardwear Integral Pro hoody for those temperatures. It's a 60/40 merino/poly blend and has thus far retained the best features of both fabrics for me – odor resistant, durable, and wicking (enough). I'm not sure of the fabric weight, but I've emailed MH and will update here when I get a response. It's pretty similar to some 150g/m pieces I've had.

Update: MH rep says the Integral Jersey fabric is 145g/m^2.

Thanks for all the replies everyone! I'm hoping to find one of these at the REI sale coming up, might get thin long wool underwear instead. I'm liking the Ice Breaker Relay; if they would just give me a different color, I'd be all over it.

For those wondering,

I went with this from Backcountry:
http://www.backcountry.com/backcountry-merino-150-base-shirt-long-sleeve-mens

Size small was already on sale for $63. Picked up some Smart Wool socks with the 20% off. Also got some Smart Wool 150 weight long underwear from REI with their discount and my mini dividend.

Thanks again for the help, I'll be looking forward to using these soon!