Both keep the rain out. What separates them is what you have on your back and the strength of the wind.
The poncho
Pros: it goes over the backpack, so the backpack stays dry without an extra cover. It goes on over your clothes in ten seconds, without taking anything off. It lets air through at the bottom, so you sweat far less than in a jacket.
Cons: it catches the wind like a sail. On an exposed ridge or cycling into the wind, it flaps and lifts. Your arms are less free for walking poles.
The rain jacket
Pros: it hugs the body, doesn’t catch the wind, leaves your arms completely free, and can be worn in town without looking like a hiker.
Cons: the backpack stays outside, so you need an extra cover. You sweat more, even with a breathable membrane.
Cycling: watch the cut
A long, loose poncho can get caught in the rear wheel: it’s a real risk of a fall. For cycling, choose a model designed for it: short at the back, with loops or hand straps that hold the fabric on the handlebars.
The hood must fit over a helmet and not block your sideways view when you turn your head.
Water column, in plain terms
It’s the height of water a fabric withstands before letting a drop through, in millimetres.
- 1,500 mm : a shower, an hour’s outing.
- 3,000 mm : sustained rain, a day’s hike.
- 5,000 mm and above : continuous rain, a backpack pressing on the shoulders (pressure forces water through faster).
Breathability (in g/m²/24 h) matters just as much: a very waterproof, barely breathable garment soaks you from the inside.
Storage, often forgotten
Poncho and jacket both pack into their pouch, but never wet : the inner coating peels and the fabric takes on a smell that won’t go away. Dry flat before folding.
In summary
Backpack and hiking: poncho. Strong wind, busy arms, city use: jacket. Cycling: a bike-specific poncho, or a jacket.
See our rain ponchos.