Is the adidas Helionic down coat warm enough for winter?

Yes for cold, dry winter days. The down and feather fill traps heat well for its weight. In heavy rain or wet snow, down clumps and loses warmth, so a water-resistant shell is better there.

How does the Helionic fit?

It has a loose fit, so it runs roomy through the body and sleeves. That makes layering easy over a hoodie or sweater. If you want a closer cut, consider sizing down.

Yes. The hood is attached, so it stays put in wind and adds coverage without a separate hat.

Can I machine wash a down puffer coat?

Usually yes, on a gentle cycle with down-safe detergent, then tumble dry low with dryer balls to break up clumps. Check the care label first, and never use fabric softener.

No. It is a down puffer for cold, dry conditions, not a rain shell. Down insulation loses loft when soaked, so wear a waterproof layer over it in wet weather.