It’s hard to believe Summer 2025 is nearing its end. While the autumnal equinox (the first day of astronomical fall) doesn’t arrive until Sept. 22, on Monday we flip the calendar to September and say hello to meteorological autumn. Although it takes some time for the weather to change, you can already sense the shifting season. The midday sun doesn’t burn quite as hot, the afternoon shadows are cool and long, and darkness is setting in before 8 o’clock.
Thankfully — assuming you want to hold on to the summer vibes — September can be a very nice month on the Cape. Despite the arrival of school buses and pumpkin spice lattes, summer does a nice job of hanging on. Average daytime highs don’t dip below 70° F until late in the month and it’s not uncommon to top 80° F a few times. Nearshore water temperatures remain mild for the next several weeks, too, so you can still get in a swim.
Looking at the overall weather pattern for the next several days, there are a couple of features to keep an eye on in an otherwise quiet stretch. We’ll be tracking a fairly potent cold front dropping southward from Canada. This front looks to rotate through New England Friday and Friday night and push offshore thereafter. Out in front of this system, moisture will be pooling up across the area late in the week, and as a result some showers are expected around the region just ahead of the holiday weekend. As of this writing, the timing looks pretty good, with the brunt of the moisture passing through the area Friday night and pushing seaward Saturday morning. If all goes well, that should set us up with fair weather for the remainder of Labor Day weekend with high pressure locked in overhead.
The other weather feature to track is an area of shower and thunderstorm activity expected to be lurking off the southeast coast of the U.S. next week. The aforementioned cold front may get hung up to our south and help generate low pressure in the vicinity of the Carolinas. There isn’t (as of right now) an overwhelmingly strong signal for this area of disturbed weather to morph into anything very noteworthy, but stationary clusters of showers and thunderstorms parked over the warm waters of the southwest Atlantic are always worth monitoring for tropical storm development. We’ll be keeping an eye on that as it could affect our weather sometime next week.
