SeasonMapCook Islands in September
September is one of Cook Islands's best months (rank 2 of 12): its 3 destinations average 85/100, led by Aitutaki at 87 — 25°C and 12 rainy days — while Rarotonga is cooler at 22°C and scores 85.
#2 of 12 months for Cook Islands · 3 destinations · updated September 2026 · climate normals from ERA5 reanalysis
Where in Cook Islands in September
| # | Place | Type | Feels-like high | Rain | Comfort | At its best |
|---|---|---|---|---|---|---|
| 1 | Aitutaki | Island | 25°C | 71 mm · 12 days | 87 tier A | Yes |
| 2 | Rarotonga | Island | 22°C | 87 mm · 10 days | 85 tier A | Yes |
| 3 | Avarua | Island | 24°C | 87 mm · 10 days | 84 tier A | Yes |
Comfort is SeasonMap's 0–100 score; each place is judged through the lens that suits it — beaches on beach weather, ski resorts on snow. "At its best" means September is one of that place's own top three months. Feels-like highs fold in humidity, wind and sun.
What's on in Cook Islands in September
- Humpback whale season · Aitutaki and 2 more places · 15 Jul – 15 Oct (usually)