I'm another big merino fan. Even better my wife has banned polyester on the reasonable ground that I stink after a ride

so I have accumulated a lot of merino, long sleeve, short sleeve, cycling specific and non-specific

.
Different weights can do different things, I have an icebreaker T-shirt, very light weight and I've worn it comfortably at 40 degrees C or as a base layer in the cold. At the other extreme a heavyweight earth wind and rider long sleeve jersey and a windproof down below zero.
Agree with yello: it is not windproof, nor does it wick well and it soaks up rain. Not sure I agree fully with Greg

, my only "sportwool" (50 merino 50% polyester) jersey is a di marchi: it holds moisture like merino and smells almost as bad as polyester.
All the items have one thing in common, they were purchased on the cheap: half price (or better in sales), from TK Maxx or gifts. If you look around you can find a bargin