Down jackets heat level Cold

The warmth of a down jacket depends on its filling (down or synthetic), weight, density (cuin) and construction (quilting, lining).
For light cold (between 10°C and 0°C), a light down jacket is sufficient. For moderate cold (down to -5°C), opt for thicker insulation. For temperatures below -10°C, opt for an extreme-cold or technical jacket.

Very warm down jackets provide effective protection in extreme cold and retain body heat for a long time, even when stationary.
However, they are often bulkier, less breathable and can restrict movement if poorly chosen. They are therefore ideal for static or extreme situations, but less suited to prolonged exertion.