NYC Fashion People Who

By Swedan MargenJanuary 8, 2026

This winter in NYC is off to a frigid start. Temperatures have been reaching arctic levels despite it not even being a month into the season. While some are bundling up under layers and layers of sweaters and coats, others—specifically NYC fashion people who "get it"—are stepping out in chic ensembles that look anything but bulky. You may be watching them as they confidently strut the streets, thinking they must be freezing, but what you don't see hidden under their lightweight coats and sweaters is a thin layer of clothing that's secretly trapping the heat. It's called the Heattech shirt, and it's become the only way to survive a New York winter while still looking cute.

The Heattech shirt is an under-$25 thermal garment from Uniqlo that comes in gorgeous neutrals like chocolate brown and ivory as well as bold colors like cherry red and dark green. It's powered by the brand's advanced Heattech technology (also found in leggings, gloves, hats, and scarves), which captures the body's moisture and converts it into heat. The shirt comes in a variety of insulation levels and styles, including Heattech, Heattech Ultra Warm, and Heattech Extra Warm Cashmere Blend. The regular Heattech style is ideal for everyday layering. The Heattech Ultra Warm is the brand's warmest option, approximately 2.25 times warmer than the original Heattech. It's designed for extreme cold with a recommended range of -4° to 50°. On the other hand, the cashmere style combines the soft, premium feel of cashmere with heat-retaining warmth. It's recommended for temperatures in the 20s to the 50s, as the fabric is a bit thinner and doesn't feature a fleece lining like the Ultra Warm does.

I've been living in New York City for almost eight years, but it wasn't until last year, after a quick scroll on TikTok, that I learned Heattech was the trick to staying warm in the winter without looking like a marshmallow under a big coat. To be honest, my jaw dropped. The next day, I went into the office and asked the other New York editors, who have been living in the city longer than I have, whether they had heard about it. Their answer was, "Of course." Quickly, I got my hands on two styles and tested them out.

Keep reading to discover my honest review of the Heattech shirts I recently tried on and wore around the city, then shop the styles and more Uniqlo winter essentials for yourself.

My Review

Heattech Ultra Warm Shirt

Recommended for temperatures between -4° and 50°, the Ultra Warm shirt is the absolute warmest option I tested. It features an ultra-stretchy, sweat-wicking outer fabric that contours for a perfect fit and a soft fleece lining. Initially, I associated this warmth level with skiing gear, so wearing it under a blazer and wool coat in the city felt unusual. However, after just one wear on the coldest day (with a real feel of 12°), it became an absolute essential in my wardrobe.

Nikki wears a fur coat, brown cashmere heattech shirt, leather pants, and black pumps. — Nikki is wearing Uniqlo's Extra Warm Cashmere Blend Turtleneck Shirt

Heattech Extra Warm Cashmere Blend Shirt

This long-sleeve shirt quickly became my favorite winter staple. When I first took it out of the box, I doubted its warming power because of its lightweight, incredibly soft material, but to my surprise, it worked and kept me warm all day. It has the luxurious feel of my designer cashmere sweaters but is thinner, making it a seamless and undetectable layer under any outfit.

I'll be stocking up on more colors of each while they're still in stock. Scroll to join me.