sept rainfall September 13, 2018 1376 × 538 When did September become a summer month? A look at rainfall back over the last 100 years shows that wet Septembers have been on a general decline since 1994. Share this: Share on X (Opens in new window) X Share on Facebook (Opens in new window) Facebook Email a link to a friend (Opens in new window) Email Share on LinkedIn (Opens in new window) LinkedIn Print (Opens in new window) Print Like Loading...