Layering apparel for cold-weather situations can not only help maintain a moderate body temperature, but it could save your life in an emergency situation.

FIRST LAYER: Base Layer

ECWCS Thermal Zone Top

Commonly referred to as longjohns or long underwear, this is the first layer you put on. It should fit closely to your body to wick moisture away, keeping you warmer. Available in both natural and synthetic fabrics, such as polyester, silk, and wool, many base layers feature four-way stretch and varying fabric weights to accommodate different activity levels. An antimicrobial treatment enhances comfort for extended wear. Selecting the best fabric and style ultimately depends on personal preference and the specific outdoor activity.

SECOND LAYER: Fleece

This layer is worn semifitted over the base layer and is designed to provide additional warmth while maintaining breathability. It can also be worn alone, thanks to its brushed softness and various weights and finishes, including water repellency and wind resistance. Anti-pilling construction not only retains body heat but also extends the garment’s lifespan. Styles range from 1/4-zip pullovers to full-zip jackets, with some being compatible with heavier parka systems.

Active Top

THIRD LAYER: Outerwear

The final layer is a protective shell worn over the base layer and fleece. This layer shields against the chilling effects of wind and water while allowing moisture from the skin to evaporate. The shell’s ability to guard against moisture is crucial for optimizing comfort and performance in extreme cold conditions.

The level of water protection in an outerwear garment is measured in millimeters (mm) and is determined by specific treatments that bond the fabric weave. Understanding these levels ensures you select the right type for your winter outdoor activity:

Puffy Jacket

• Water-repellent – Tightly woven and sometimes chemically treated with a durable water-repellent finish. Provides minimal protection against rain and snow; once saturated, this fabric loses its effectiveness.
• Water-resistant – Similar to water-repellent fabric but resists saturation longer before losing effectiveness.
• Waterproof – Tightly woven and chemically treated with a higher amount of durable water-repellent finish to completely block water. Maintains water protection even after prolonged exposure to rain, sleet, or snow.

Specialized laminates, such as GORE-TEX®, Omni-Dry®, HyVent™, and Dry-Plus®, can be applied to synthetic fabrics for enhanced waterproof protection. These laminates reduce fabric pores to be smaller than a drop of water while remaining larger than a vapor molecule, resulting in a waterproof yet breathable garment. For a garment to be considered 100% waterproof, all seams must also be sealed with waterproof tape.

Your final layer may also incorporate varying levels of insulation—both synthetic and natural—for added warmth as needed. Some parkas feature adjustable, removable hoods and zippered ventilation to help regulate body temperature.