I have covered my recommendations for a good top layer - the rain gear piece. Now let's discuss the bottom layer - equally important but not as sexy! There is really only one rule - NO COTTON! The material touching your little one's skin should wick moisture away and keep them warm. There are a lot of different makes and models out there but the materials that work best are wool, wool/silk blend, silk and polyester. The Waldorf preference is always going to be a natural fiber and I will discuss those first...but your budget may not fall on that side of the fence so I will also talk about synthetic options that work.
Wool
Wool long underwear has a lot of pros: it is breathable, warm in the winter, cool in the summer, wicks moisture from the skin, insulates even when wet, odor resistant, sustainable and a natural fiber. Its con list is pretty short: it is expensive. Some folks will say it is hard to take care of but in my experience merino long underwear is about the same to maintain as any synthetic I have used. There are several good brands of wool base layer. Here are the ones that I am familiar with.Icebreaker
Icebreaker is a brand carried at REI, Cabelas, amazon. com and more. It is manufactured from New Zealand merino wool and is machine washable. Ours have been dried accidentally a few times and do not seem worse for the wear. I have found great deals on both REI outlet and Sierra Trading Post. My high-sensory boy loves this stuff and wears it top and bottom almost every day of the year.Polarn O. Pyret
Polarn O. Pyret is a Swedish company committed to good-looking clothes that let children be children. They offer an immense and impressive selection of merino items for babies and children. Mittens, socks, long underwear, rompers, balaclavas and hats. You name it, they make it out of wool. Their rain gear is awesome, too! Their stuff is pricey, but they have fairly regular sales and everything I have purchased from them is very high quality.Hocosa
Hocosa is a Swiss brand that offers wool and wool/silk (70/30) blend products. Their products are widely available on amazon.com and several Waldorf websites. I have not personally used their products, but they come highly recommended. The wool/silk blend products work well for kids complaining of the "itchiness" of 100% wool products.Silk
Silk is smooth and soft against the skin and as such is a great choice for those with really sensitive skin. That said, silk does not retain warmth as well when wet, is expensive, longer drying and may need to hand-washed. It is not the first choice for the northwest climate due to our frequent rain and almost constantly wet winters. It is certainly better than cotton, though, and if your child cannot bear wool or synthetic materials, this is a good choice. The brand that seems to consistently offer kid's long underwear in 100% silk is Thermasilk and it is available on amazon.com and campmor.comSynthetic Fabrics
Polypropylene was first polymerized in 1954 and is the second most important plastic (based on revenues). It also keeps you warm and dry. If you cannot fit wool or silk into your budget then polypropylene or other polyesters will be your answer. Your child must have a thin, moisture-wicking, insulating layer, especially during the colder part of the year, and plastic is ready to step up and perform well. Most readily available long underwear sold by REI, LL Bean, Land's End and campmor.com is made of synthetic materials. Patagonia Capilene is an extremely high-quality synthetic line, but if you can afford it then you can afford wool :). The pros of synthetic base layers are: they are moisture wicking, easy to care for and affordable. The cons are: they are a petroleum based product and are prone to retaining odors.What Items Does My Child Need?
Every child is different. And you know your child better than anyone. A good basic base layer stock includes 2-3 long-sleeved tops, 1-2 tank or sleeveless tops and 2-3 bottoms. If you know your child cannot tolerate sleeves, buy more tanks. If they are always cold, skip tanks altogether and buy an extra long-sleeved top. Buy everything a size up to get a little longer use and remember that you will also use these items when skiing, sailing, camping and hiking. Your child may also want to wear them for pajamas. These items will go on sale in the summer and that is a great time to stock up!Here is a great link to REI's base layer comparison.
I hope this will help you find some clothing to help keep your child(ren) warm in all weather! Next topic will be Accessories (Hats, Gloves, Mittens and Socks)...
Happy Layering!