Hawaii weather in September
The state broadly agrees with itself in September: afternoons run 90° in Kahului (Maui) and 83° in Hilo, with everywhere else in between.
Based on 5 weather stations. Five stations across four islands, all near sea level — the leeward-versus-windward difference shows up here, but upcountry and volcano-summit weather is another world these numbers don’t reach.
Oahu
Highs near 88°, nights around 75°, and 0.9 in of rain in a typical September.
| Place | Highs / lows | Wet days | The short version |
|---|---|---|---|
| Honolulu | 88° / 75° | 2 | Summer heat, September prices, and the beach back to yourself. |
Maui
Highs near 90°, nights around 71°, and 0.5 in of rain in a typical September.
| Place | Highs / lows | Wet days | The short version |
|---|---|---|---|
| Kahului (Maui) | 90° / 71° | 1 | The island's hottest and emptiest month — take it. |
Kauai
Highs near 85°, nights around 75°, and 2.2 in of rain in a typical September.
| Place | Highs / lows | Wet days | The short version |
|---|---|---|---|
| Lihue (Kauai) | 85° / 75° | 5 | School's back on the mainland, and the island quiets down. |
Big Island, Kona side
Highs near 87°, nights around 75°, and 0.5 in of rain in a typical September.
| Place | Highs / lows | Wet days | The short version |
|---|---|---|---|
| Kailua-Kona | 87° / 75° | 1 | Residents get their beaches back for a few weeks. |
Big Island, Hilo side
Highs near 83°, nights around 70°, and 8.7 in of rain in a typical September.
| Place | Highs / lows | Wet days | The short version |
|---|---|---|---|
| Hilo | 83° / 70° | 15 | Warmest month here, and the sky lets up a little. |
Each place above has its own page for the full story — what the month feels like, what to pack, and whether the timing is right.