To stay warm in winter is a question of what you wear. Not all clothes are equal in protecting you from the cold. By using sweaters and booties as examples, this post educates about booties and sweater material properties. As a result it explains which clothes and materials are best for which winter climate. Read to learn more on staying warm in booties and sweater in your weather.
- Insulation differs with booties and sweater material properties
- A winter sweater of one climate region fails in another
- Cotton sweaters are for warm/hot climate region winters
- Insulation is key in winters of cold climates
- Examples of good and bad insulators in apparel
- The knit/weave also plays a role
- Sweaters that I wear in winter
- References
- Ageless Style Linkup – sweaters and booties
Updated: 1/4/2022
Disclosure: There are affiliate links in this post.
Insulation Differs with Booties and Sweater Material Properties
A while ago, I talked about keeping your feet warm at frigid temperatures. In today’s post, let’s talk about booties and sweaters to create ageless style and stay warm when the Polar Vortex extends south.
A Winter Sweater of One Climate Region Fails in Another
Sweaters are a fall/winter essential in all cold climate regions. But not every sweater works for every climate region. A cotton cable knit sweater is a great way to create a winter look down in California or anywhere a long the coast of the Gulf of Mexico. However, this sweater would be unsuitable for wet, humid just above the freezing point weather of Washington state, the blizzards in the Midwest, Canada, Alaska or even the East Coast. In these climates, cashmere, wool, silk and qivuit (musk ox under wool), or any blend of them are much better. Read more on the coziness of wool and acrylics as an example of the benefits of worsted blends.

Cotton Sweaters Are for Warm/Hot Climate Region Winters
The physical properties of the yarns are the reason. Cotton absorbs water, i.e. sweat. It is comfortable to wear in hot climates as it breathes, and is slow to dry. Thus, one gets some wanted cooling on a hot summer day. However, the slowness in drying means in a cold climate that the body sweat may even freeze. Cotton rarely gets electrostatic, which happens to many fabric in cold dry continental climate like in Central Canada, Siberia or Interior Alaska.
Insulation Is Key in Winters of Cold Climates
A key factor for winter clothing in general is the thermal conductivity. This term refers to the heat transfer by molecules. You know this physical phenomenon very well, when you own an iron pan with iron handle. Even though the handle isn’t in contact with the heat source, it gets hot by exactly this thermal conduction.
In case of your feet or body, which are both warmer than the cold ground or ambient air, the body heat flows to the colder ground or air. Thus, you need a fabric that a low rate of heat conduction across the fabric, i.e. a low thermal conductivity. In other words, the fabric provides high thermal insulation from the cold.

Examples of Good and Bad Insulators in Apparel
Fabrics with low thermal conductivity are all kinds of wool with expensive musk ox wool (qiviut) being the best. Rubber has a high thermal conductivity. Thus, rubber booties without insole are not a good idea at below freezing temperatures. Norwegian wool felt booties aka loben boots are great at temperatures in the negative digits (less than -18oC).
In general as a material, thermal conductivity of cotton, wool and fleece are 0.168-0.184, 0.04-0.07, and 0.035 W/(m·K), respectively. This means you stay warm longer in fleece than in wool than in cotton.
The Knit/Weave Also Plays a Role
Of course, the thickness and tightness of a fabric play a role. A single jersey cotton fabric with a surface density of 1 gram per square centimeter (g/m2; 0.23 oz per square inch) has a thermal conductivity of 0.035 W/(m·K). The thermal conductivity of interlock and 1×1 rib cotton fabrics is higher than that of cotton jersey. This is due to the fact that air is a bad conductor and as the fabric gets tighter the space and amount of “air pores” goes down. The thermal conductivity of polyester single jersey at same density as that of the cotton jersey is 0.032 W/(m·K). This means one is better off with a polyester sweater in cold climate than with a cotton sweater of same tightness of the knit. Again, when the knit gets tighter the thermal conductivity goes up as the pore space for still air goes down. The thermal conductivity of wool felts with about 1 g/m2 is about 0.094 W/(m·K). Norwegian booties are made from that.
Sweaters that I Wear in Winter
Now to my sweaters that suit me well from when we have “warm weather” due to Chinook, to frigid cold when cold air builds over the Interior and northwestern Canada (to get ready to bring a cold snap to southern Canada and the northern US). 😉 I wear the cotton sweater at temperatures around the freezing point. Doing so works in the dry continental, calm wind climate of the Interior. I wear my wool sweaters (e.g. Fair Isle sweater, Irish cable knit sweater) when temperatures get below -10F (-17.2o. When temperatures plump below -20F (-28.9o) nothing helps any better than layers, layers and even more layers. Layering is key. More in this guide on stylish winter layering looks.
Stylist’s tip: Taking a layer down should not break your look. This means you have to style several outfits in one so to speak.
Learn how to create stylish cold wet weather outfits in the guide at the link.
In the posts at the links, you can find guides on
When you liked the outfit recipes of this post, and want recipes for all kind of dressing situation in midlife, buy my book How to Dress for Success in Midlife.
I read an article on booties and sweater material properties. Check it out too to stay warm in cold weather. #fashion #stayingwarm Click To Tweet
References
Mölders, N., 2019. Outdoor Universal Thermal Comfort Index Climatology for Alaska, Atmosphere and Climate Sciences, DOI: 10.4236/acs.2019.94036
Mölders, N., Kramm, G., 2014. Lectures in Meteorology, Springer, New York.
Oğlakcioğlu, N., Marmarali, A., 2007. Thermal Comfort Properties of Some Knitted Structures. Fibres & Textiles in Eastern Europe, 15, 64 – 65.
Ageless Style Linkup – Sweaters and Booties
Welcome to the Ageless Style Linkup party. Let’s see your ageless style.
Please visit some of the linked up posts and spread the word about the party for more Ageless style inspirations. Please follow us on at least one of our platforms each. Thank you.
Ana ~ Mrs. American Made blog
Daenel ~ Living outside the stacks
Debbie ~ Fashion Fairy Dust
Jennie ~ A Pocketful of Polka Dots
Jodie ~ Jodie’s Touch of Style blog
Nicole ~ High Latitude Style Newsletter
Paula ~ Dimples on my What blog
Shelly ~ The Queen in Between blog
Yvonne ~ Funky Forty blog
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Photos of me: G. Kramm
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