Rain Jackets

Not all raincoats are 100% waterproof, but you can get waterproof rain jackets that are seam-sealed to make them fully waterproof.

Waterproof ratings are given in mm, based on the amount of water the fabric can withstand during a test with a tube of water with a 1 inch diameter. Rain jackets with a rating between 0mm and 1,500mm are water resistant, 1,500mm to 5,000mm is enough to designate a jacket waterproof, while 10,000mm to 20,000mm are referred to as highly waterproof.

You may have a whole in it, or the limit of its waterproofing may have been reached. It’s also possible that the dampness you feel is caused by condensation from the cooling of hot air coming from your skin.