Layering is essential to stay both warm and dry, but not hot and sweaty, when walking in cooler weather. From the base, you need a shirt that will draw away any moisture, a jacket or vest to insulate and cut the wind, and a waterproof layer if you are in a wet climate.
This waterproof shell jacket is what I like to wear most of year as my outer layer. Wear it over a fleece vest in colder weather. It is lightweight and breathable. Comes in a variety of colors and sizes 1X to 3X.
This soft long sleeve tee wicks away the sweat to keep you dry on cooler walks. The wicking fabric is far superior to cotton for keeping you dry yet insulated from the chill. I wear a similar long sleeve technical t-shirt on all of my cool walks - it's perfect under a wind-resistant or waterproof jacket. The antimicrobial finish helps keep odor away. It comes in plus sizes 1-6.
Sporthill makes high quality gear for walkers and it is great to see them now producing plus-size styles. This v-neck long-sleeved top is made in wicking DriTech Lite, a polyester/lycra blend. Whether you get wet from sweat or from rain, it will help keep your skin dry and will dry fast once wet. It also looks sporty so you can feel athletic, with contrast piping. Comes in plus sizes 1X-4X.
This top is made with Coolmax Extreme fabric, which provides a great base layer to transport moisture away from your skin to the outer surface of the garment where it can quickly evaporate. Available in 1X and 2X sizes.

Wendy Bumgardner © 2007The Sport Fleece Jacket is a great design for fitness walking and nordic walking in cooler weather. It provides an insulating layer that also wicks aways sweat. It comes over the hip but has a tailored profile so it won't get in your way when you move your arms or use fitness walking poles, and is easier to layer under a waterproof jacket. It has two zip pockets in front and two inner patch pockets. Wear this over a base layer shirt on cool and dry days, or wear as the insulating layer beneath a waterproof/windproof jacket and over a base layer shirt on cold and wet days. It comes in plus sizes 1X-3X.
Jackets made of Polartec performance fleece are both breathable and insulating. Choose from designs including pullover and zip jackets. You can wear them under a waterproof or windproof shell as your insulating layer.
When rain isn't a problem but you need an outer layer to cut the wind or chill, this breathable windbreaker is an essential. It has zippered pockets and elastic cuffs. Team this with one of the shirts and you are good to go. Plus sizes 1-4.
Sometimes all you need or want is a vest to cut the wind, layered over your favorite walking top. This vest has two front zip pockets for essentials. Ot is made of Wind-Bloc Polatec fleece, which is water-resistant and windproof. Comes in plus sizes 1X-3X.
This jacket is water-resistant rather than waterproof. It combines an outer nylon layer with an inner performance fleece layer. You can reverse them if you want the fleece out and nylon in. Best of all, it has a hood. Perfect for climates where you don't walk for long in rain but need a versatile winter jacket combo. Available in plus sizes 1X-6X.
This windbreaker vest may be just the layer you need on a spring or fall day. It is light and packable. It has a front zip pocket. Plus sizes 1X to 4X.
Underneath it all you need a sports bra that can help support and wick away moisture. This double layer sports bra can do double duty. Plus sizes 0X-6X.