READ: RUNNING JACKET BUYING GUIDE / WHAT TO WEAR RUNNING IN THE RAIN
Waterproof ratings (measured in mm) indicate how much rain a jacket handles. Look for 10,000mm+ for sustained wet weather. Breathability ratings (measured in g/m²/24hrs) show how well moisture escapes from inside. High breathability (20,000g+) prevents sweat buildup during hard efforts. Jackets with pit zips and back vents boost airflow when intensity rises.
Packable jackets compress into pockets or running vests for emergency weather protection. Lightweight shells (under 150g) barely register during long runs. Running insulated jackets with synthetic fill or down provide warmth for recovery jogs in freezing conditions. Gilets balance core warmth with arm mobility for changeable spring and autumn days.
Fit affects performance. Athletic cuts reduce the fabric flap during fast sessions. Longer backs prevent exposure when leaning forward. Hood designs that fit over or under caps keep rain off your face. Reflective details add visibility during dark commutes. Shop running jackets and gilets at Runners Need for protection in British weather.