You don’t want to be wearing a heavy, insulated waterproof in summer, as when it rains it’s usually reasonably warm and humid, and an insulated jacket will make you sweaty on the inside even if it does keep the rain out.
An easily packed jacket is a versatile one, and one that packs down to a small size is obviously more easily stowed in smaller summer day packs. Small pack size usually means lighter too. Look for jackets that pack away into their own pockets, built-in pouches or which come with small stuff sacks.
Some jackets are more waterproof than others. The higher the jacket’s ‘hydrostatic head’ the more resistant to precipitation it will be. This info should be available on the garment’s swing tag or on the manufacturer’s website and will be written as ‘mm H2O’ – around 20,000mm H2O is a good figure to look for.
Your jacket also needs to be breathable, especially in summer when it’s warmer and more humid. Look for the jacket’s ‘Moisture Vapour Permeability’ rating, which should be around 20,000/m2/24hrs to be able to claim breathability.
These are important as they’re where unwanted moisture is most likely to get in. Laser cut and glued seams are best since they don’t involve putting holes into the fabric, and they also keep the weight down. If they’re taped then that’s even better.
Water resistant zips are vital, and an adjustable, well-fitted hood will prove its worth in downpours. Look out for helmet compatible hoods if your activity of choice involves wearing a lid. Pit zips are also great in warmer weather as they help to regulate your body temperature by letting air in and out. Some jackets will have large pockets with mesh inners which act as ‘vents’ when the zips are unfastened.
For gear reviews of lightweight jackets and more check out our gear pages.