SeasonMapRarotonga (Cook Islands) weather in September
Cook Islands
September in Rarotonga: warm, rainy, with clean air — one of the best months to visit.
#2 of 12 months in Rarotonga · #495 of 1383 destinations to visit in September · comfort 85/100 (tier A)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Rarotonga in September
Other months in Rarotonga
Rarotonga's forum calls October-November a favorite window, technically within cyclone season but with genuinely low odds of a storm actually hitting during a visit. Regulars note November runs noticeably more humid than October, though still comfortable enough to sleep without air conditioning, and flag it as low season for tourism, meaning better accommodation rates.
Add your own note from Rarotonga's card on the map.
Rarotonga climate normals — September
| Daytime high | 25°C / 76°F | 🌤 warm |
|---|---|---|
| Nighttime low | 18°C / 65°F | |
| Feels like (high) | 25°C / 77°F | |
| Sea temperature | 24°C / 75°F | 🙂 pleasant |
| Rainfall | 83 mm / 3.3 in | 🌧 rainy |
| Rainy days | 10 days | |
| Humidity | 76% | 💦 very humid |
| Dew point | 17°C / 62°F | |
| Sunshine | 9.9 h/day | |
| Daylight | 12 h | |
| Wind | 31 km/h / 19 mph | |
| Air quality (US AQI) | 46 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Rarotonga in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyDrier, cooler half of the year, school holidays in 3 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Rarotonga's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherRarotonga's weather doesn't swing hard through the year — comfort stays fairly steady in every month.
What's on in Rarotonga in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Season
Drier, cooler half of the year
1 May – 31 OctDry seasonCrowdedMay to October is the drier, cooler half and the island's high season. The cross-island track is at its least slippery and the lagoon on the south side is calmest early.
- Nature
Humpback whale season
15 Jul – 15 Oct · usuallyHumpbacks arrive from July and stay into October, often just beyond the reef where the drop-off is close to shore. Plenty of sightings happen from the coast road.
Nearby, and something's on
Within 300 km of Rarotonga — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Rarotonga?
Rarotonga in September — FAQ
- Is September a good time to visit Rarotonga?
- September in Rarotonga: warm, rainy, with clean air — one of the best months to visit. It ranks #2 of 12 months for Rarotonga on SeasonMap's comfort score (85/100).
- What is the weather like in Rarotonga in September?
- In September, Rarotonga averages a daily high of 24.5°C and a low of 18.2°C, with about 83 mm of rain over roughly 10.1 rainy days.
- What is the air quality in Rarotonga in September?
- Rarotonga has a mean US Air Quality Index of about 46 in September.
Other months in Rarotonga
Compare Rarotonga in September
Warmer or cooler than Rarotonga in September
Similar destinations in Pacific — September
Within 300 km: Avarua's Humpback whale season around 15 Jul – 15 Oct, and Aitutaki's Humpback whale season around 15 Jul – 15 Oct.