Running in colder weather means layers, and my favorite base layer is Cuddl Duds. In this pic from the recent CareNet Feed the Need 5K, I am wearing the ActiveLayer Long Sleeve V Neck. It's sweat-wicking so it keeps me dry, and has thumb holes on the cuff (which I love!). It's so thin, soft, warm, & comfy that it has become one of my favorite shirts for anytime layering, not just for running.
Actually, I could say that about all my Cuddl Duds. I also own several of the Softwear Lace Edge with Smart Layer shirts, and Softwear with Smart Layer leggings. They all help keep me warm without adding uncomfortable bulk, and they are perfect under other running clothes, or with sweaters and jeans.
I've purchased Cuddl Duds at both Kohl's and Target at very affordable prices. They are also available online, with free shipping. The website also shows some cute suggestions about how to layer all their different products - all designed to make you want to buy more, I'm sure, but I enjoy cyber window shopping.
Finally, I was excited to notice when I pulled up the website to link to this review that their newest leggings have pockets! Pockets are such an awesome feature, and I really don't understand why more clothes don't have them. I'm not carrying a purse when I run, so please give me somewhere to stash some lip balm and my car key.