Has it ever happened to you that you put on a warm shirt to go running outside and discovered that it was a bit too warm? Maybe you put on a lightweight shirt and later found yourself staying out for an extended period of time and starting to feel cold? Surely there must be an easy solution to this problem than having to wear or take off multiple layers? Yes indeed, there is and it's called merino wool.
I discovered the joy of running in merino wool last year when I picked up a merino wool running shirt from REI. It's been a year, running through four seasons (or however many you can categorize California weather into) and I've been using it on a regular basis. Based on that experience, I can say that it's probably my favorite type of running shirt.
The cool thing about merino wool is that you can wear it when it cold outside or warm outside and it'll still maintain a comfortable temperature.It dries fast and doesn't hang to to sweat like cotton. I've used it in the 40F to 80F range with nary a complaint. Often, I might go for a hike/run combo and sometimes, I end up going elsewhere after the run, e.g., grab a bite to eat. The body tends to cool down after a while and it's in these moments that I find my merino wool shirt very convenient - I don't need to put on another layer. Then, of course, there are other benefits such as not having to worry about the shirt shrinking due to repeated wash-and-dry cycles and that it doesn't itch unlike some other materials. For temperatures below 40F, a lightweight shirt might not be sufficient depending on how you deal with cold. Likewise, once it gets above 80F, you might want to look at something even lighter such as some technical shirts made by Sugoi.
REI is a great place to buy merino wool shirts. Another good place to snag some bargains is Sierra Trading Post. Keep in mind that merino wool shirts typically cost more than a regular polyester shirt, but trust me, it's worth the extra money.