September is one of the warmer months of the year in Honolulu, with average highs near 27.9°C and lows around 24.9°C (mean 26.4°C). It is one of the drier months, averaging 47 mm of rainfall and 74% relative humidity across the period.
September is one of the warmer months of the year in Honolulu. Across 45 years of records, the warmest Septembers in Honolulu were 2014 and 2019 — when the month averaged 27.6°C — while the coldest was 1983 at 24.7°C. Typical September days reach 27.9°C with nights near 24.9°C. The long-term trend is warming, about 0.3°C per decade.
September is one of the drier months in Honolulu, averaging 47 mm of rainfall. The wettest September on record was 1982 with 296 mm, while the driest was 2010 at 5 mm.
Relative humidity in Honolulu during September averages 74%. The most humid September was 1982 at 81%, and the least humid was 1995 at 70%.
September receives about 6.1 kWh/m²/day of solar energy in Honolulu. The sunniest Septembers were 2020, 2022 and 2024, among others at 6.5 kWh/m²/day, and the cloudiest was 1986 at 5.4.
Average wind speed in Honolulu during September is 5.4 m/s. The windiest September was 2005 at 6.8 m/s, while the calmest was 1986 at 3.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 25.8°C | 26.2°C | 26.4°C | 26.7°C | 27.0°C | +1.2°C |
| Avg High | 27.2°C | 27.7°C | 27.9°C | 28.2°C | 28.6°C | +1.4°C |
| Avg Low | 24.4°C | 24.7°C | 24.9°C | 25.2°C | 25.3°C | +0.9°C |
| Avg Rain | 80 mm | 19 mm | 36 mm | 64 mm | 32 mm | -49 mm |
September temperatures in Honolulu have risen by about 1.4°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 22.5°C (1983) to a record high of 30.6°C (2014).
Rainfall in September is one of the drier months, averaging 47 mm, with a wettest year of 296 mm.
A quieter season to visit Honolulu
If your dates are flexible, the more temperate months of February and March tend to be the most comfortable for visiting Honolulu. That said, September — with days averaging 27.9°C and nights around 24.9°C (mean 26.4°C) and moderate rainfall (47 mm) — can still be rewarding for travellers who don't mind the warmth, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 29.0°C | 27.3°C | 25.6°C | 29.7°C | 24.8°C | 11 mm | 71% | 5.3 m/s | 6.4 |
| 2024 | 28.9°C | 27.3°C | 25.7°C | 29.8°C | 25.0°C | 11 mm | 70% | 5.3 m/s | 6.5 |
| 2023 | 28.6°C | 27.0°C | 25.4°C | 29.4°C | 24.8°C | 11 mm | 72% | 6.1 m/s | 6.4 |
| 2022 | 28.8°C | 27.1°C | 25.4°C | 29.6°C | 24.9°C | 50 mm | 74% | 4.9 m/s | 6.5 |
| 2021 | 27.5°C | 26.0°C | 24.5°C | 28.1°C | 24.0°C | 76 mm | 76% | 6.4 m/s | 6.3 |
| 2020 | 28.7°C | 27.0°C | 25.3°C | 29.7°C | 24.7°C | 31 mm | 72% | 5.5 m/s | 6.5 |
| 2019 | 29.0°C | 27.6°C | 26.3°C | 29.8°C | 25.8°C | 117 mm | 76% | 5.4 m/s | 6.1 |
| 2018 | 27.9°C | 26.6°C | 25.2°C | 28.8°C | 23.8°C | 150 mm | 79% | 4.8 m/s | 6 |
| 2017 | 28.7°C | 27.0°C | 25.3°C | 29.7°C | 24.5°C | 29 mm | 72% | 4.2 m/s | 6.4 |
| 2016 | 27.6°C | 26.4°C | 25.1°C | 28.7°C | 24.2°C | 79 mm | 78% | 6 m/s | 5.9 |
| 2015 | 28.4°C | 27.2°C | 26.0°C | 29.7°C | 24.7°C | 137 mm | 78% | 5.2 m/s | 5.7 |
| 2014 🔥 | 29.4°C | 27.6°C | 25.9°C | 30.6°C | 24.9°C | 42 mm | 73% | 4.1 m/s | 6.4 |
| 2013 | 28.1°C | 26.6°C | 25.1°C | 29.3°C | 24.4°C | 36 mm | 73% | 5.8 m/s | 6.2 |
| 2012 | 27.0°C | 25.5°C | 24.0°C | 27.8°C | 23.6°C | 37 mm | 74% | 6 m/s | 6.2 |
| 2011 | 27.8°C | 26.1°C | 24.4°C | 28.7°C | 23.7°C | 6 mm | 71% | 5 m/s | 6.4 |
| 2010 | 27.7°C | 26.0°C | 24.3°C | 28.6°C | 23.7°C | 5 mm | 71% | 5.3 m/s | 6.4 |
| 2009 | 28.0°C | 26.5°C | 24.9°C | 29.0°C | 23.9°C | 27 mm | 73% | 6 m/s | 6.4 |
| 2008 | 27.8°C | 26.1°C | 24.5°C | 28.5°C | 24.0°C | 32 mm | 72% | 4.9 m/s | 6.3 |
| 2007 | 27.8°C | 26.4°C | 25.0°C | 29.3°C | 24.4°C | 24 mm | 73% | 6.2 m/s | 6.1 |
| 2006 | 27.9°C | 26.4°C | 24.9°C | 28.7°C | 24.2°C | 32 mm | 73% | 5.8 m/s | 6.3 |
| 2005 | 27.9°C | 26.6°C | 25.2°C | 29.2°C | 24.2°C | 67 mm | 75% | 6.8 m/s | 6.1 |
| 2004 | 28.7°C | 27.2°C | 25.7°C | 29.9°C | 25.2°C | 48 mm | 73% | 5.9 m/s | 6.3 |
| 2003 | 28.2°C | 26.7°C | 25.2°C | 29.4°C | 24.6°C | 48 mm | 72% | 5 m/s | 6.4 |
| 2002 | 27.9°C | 26.3°C | 24.8°C | 29.2°C | 24.2°C | 26 mm | 72% | 5.2 m/s | 6.2 |
| 2001 | 27.5°C | 26.1°C | 24.6°C | 28.8°C | 23.8°C | 35 mm | 72% | 6.1 m/s | 6.1 |
| 2000 | 27.3°C | 25.8°C | 24.3°C | 28.2°C | 23.2°C | 26 mm | 75% | 5.3 m/s | 5.9 |
| 1999 | 27.1°C | 25.5°C | 24.0°C | 27.6°C | 23.6°C | 9 mm | 71% | 6.2 m/s | 6.5 |
| 1998 | 26.9°C | 25.5°C | 24.1°C | 27.9°C | 23.1°C | 5 mm | 72% | 6.3 m/s | 6.2 |
| 1997 | 28.2°C | 26.7°C | 25.3°C | 29.3°C | 24.3°C | 16 mm | 73% | 5.9 m/s | 6.3 |
| 1996 | 28.2°C | 26.8°C | 25.3°C | 29.3°C | 24.4°C | 21 mm | 72% | 5.5 m/s | 6.1 |
| 1995 | 28.3°C | 26.7°C | 25.1°C | 29.6°C | 23.9°C | 8 mm | 70% | 4.3 m/s | 6.1 |
| 1994 | 27.4°C | 26.1°C | 24.8°C | 28.7°C | 23.7°C | 13 mm | 77% | 5.8 m/s | 5.8 |
| 1993 | 27.9°C | 26.3°C | 24.7°C | 29.2°C | 23.3°C | 10 mm | 73% | 4.6 m/s | 6 |
| 1992 | 27.4°C | 26.1°C | 24.8°C | 29.3°C | 23.3°C | 49 mm | 79% | 5.7 m/s | 5.5 |
| 1991 | 27.4°C | 25.9°C | 24.4°C | 28.4°C | 23.5°C | 40 mm | 75% | 4.7 m/s | 5.9 |
| 1990 | 27.7°C | 26.2°C | 24.8°C | 28.8°C | 24.0°C | 17 mm | 75% | 6.2 m/s | 5.9 |
| 1989 | 27.3°C | 25.8°C | 24.3°C | 28.7°C | 23.3°C | 25 mm | 74% | 6 m/s | 5.9 |
| 1988 | 27.6°C | 26.1°C | 24.6°C | 28.8°C | 24.0°C | 45 mm | 75% | 5.3 m/s | 6.1 |
| 1987 | 27.8°C | 26.4°C | 25.1°C | 29.3°C | 23.2°C | 61 mm | 76% | 4.7 m/s | 5.5 |
| 1986 | 28.0°C | 26.5°C | 25.1°C | 29.3°C | 24.2°C | 91 mm | 76% | 3.9 m/s | 5.4 |
| 1985 | 27.2°C | 25.7°C | 24.2°C | 28.6°C | 23.2°C | 33 mm | 75% | 4.3 m/s | 5.7 |
| 1984 | 27.3°C | 25.8°C | 24.3°C | 28.4°C | 23.6°C | 26 mm | 76% | 4.7 m/s | 5.7 |
| 1983 ❄️ | 25.9°C | 24.7°C | 23.4°C | 26.9°C | 22.5°C | 86 mm | 80% | 5.6 m/s | — |
| 1982 🌧️ | 26.2°C | 25.1°C | 24.0°C | 27.1°C | 22.9°C | 296 mm | 81% | 5.5 m/s | — |
| 1981 | 27.7°C | 26.2°C | 24.7°C | 29.0°C | 23.6°C | 62 mm | 75% | 5.1 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 27.9°C with lows near 24.9°C (mean 26.4°C), based on 45 years of NASA POWER data.
September averages 47 mm of rainfall in Honolulu, one of the drier months. The wettest on record was 296 mm in 1982.
The hottest September reached 30.6°C in 2014. The coldest dipped to 22.5°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.4°C. Daytime highs moved from 26.9°C to 28.6°C and overnight lows from 24.1°C to 25.3°C over the same span.
September is one of the warmer months of the year in Honolulu and one of the drier months, so plan for around 27.9°C daytime highs and 24.9°C at night.
Not quite — September is the 12th coolest month in Honolulu, averaging 26.4°C.
For September in Honolulu, pack light layers you can adjust through the day, with typical highs of 27.9°C and lows of 24.9°C.
Relative humidity in September averages 74% — moderately humid.
Average wind speed in September is 5.4 m/s. The windiest September on record averaged 6.8 m/s (2005).
The wettest September on record was 1982 with 296 mm. On average, September sees 47 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Honolulu behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
