Typical September weather
Cape Cod
Massachusetts · September
73° days
56° nights
about 5 rainy days · 12½ hours of daylight · ocean 67°
What to pack
- Light jacket
- Sunscreen
What September feels like
Locals call this their real summer: the sea holds its heat well past Labor Day while the beaches empty overnight, and restaurants keep normal hours through the month. The one caveat is the tropics — this is the heart of the season when a storm can track up the coast.
Expect about 5 days with real rain — enough to notice, not enough to plan around.
Can you swim?
The ocean runs about 67° — brisk but swimmable.
The numbers
| Typical high | 73° |
|---|---|
| Typical low | 56° |
| Days with real rain | 5 |
| Total rain | 3.9 in |
| Water temperature | 67° |
| Sunrise / sunset (mid-month) | 6:21 am / 6:50 pm |