December is one of the cooler months of the year in Kailua, with average highs near 24.6°C and lows around 23.2°C (mean 23.9°C). It is a relatively wet time of year, averaging 71 mm of rainfall and 77% relative humidity across the period.
December is one of the cooler months of the year in Kailua. Across 45 years of records, the warmest December in Kailua was 2024 — when the month averaged 25.3°C — while the coldest was 1982 at 22.5°C. Typical December days reach 24.6°C with nights near 23.2°C. The long-term trend is warming, about 0.3°C per decade.
December is a relatively wet time of year in Kailua, averaging 71 mm of rainfall. The wettest December on record was 2021 with 234 mm, while the driest was 2024 at 6 mm.
Relative humidity in Kailua during December averages 77%. The most humid December was 1987 at 80%, and the least humid was 1994 at 71%.
December receives about 3.9 kWh/m²/day of solar energy in Kailua. The sunniest December was 2005 at 4.5 kWh/m²/day, and the cloudiest were 1987 and 1992 at 3.3.
Average wind speed in Kailua during December is 5.5 m/s. The windiest December was 2001 at 7.4 m/s, while the calmest were 2009 and 2010 at 3.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 23.3°C | 23.5°C | 24.0°C | 24.1°C | 24.8°C | +1.5°C |
| Avg High | 24.0°C | 24.1°C | 24.8°C | 24.8°C | 25.6°C | +1.6°C |
| Avg Low | 22.7°C | 22.9°C | 23.3°C | 23.4°C | 24.0°C | +1.3°C |
| Avg Rain | 90 mm | 49 mm | 60 mm | 84 mm | 77 mm | -13 mm |
December temperatures in Kailua have risen by about 1.7°C between 1981–1985 and 2021–2025.
December has ranged from a record low of 20.1°C (1988) to a record high of 27.1°C (2024).
Rainfall in December is a relatively wet time of year, averaging 71 mm, with a wettest year of 234 mm.
A good time to visit Kailua
December is a good time to visit Kailua, with days averaging 24.6°C and nights around 23.2°C (mean 23.9°C, close to Kailua's yearly average) and moderate rainfall. February and April are marginally more temperate, but December still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 25.8°C | 25.1°C | 24.3°C | 26.9°C | 23.4°C | 63 mm | 77% | 4.5 m/s | — |
| 2024 🔥 | 26.2°C | 25.3°C | 24.3°C | 27.1°C | 23.4°C | 6 mm | 74% | 4.5 m/s | 4.4 |
| 2023 | 25.1°C | 24.4°C | 23.6°C | 26.7°C | 22.5°C | 28 mm | 77% | 5.5 m/s | 3.9 |
| 2022 | 25.7°C | 24.8°C | 23.9°C | 26.6°C | 22.5°C | 79 mm | 76% | 5.2 m/s | 3.9 |
| 2021 🌧️ | 24.7°C | 24.0°C | 23.4°C | 26.3°C | 21.6°C | 234 mm | 80% | 6.8 m/s | 3.5 |
| 2020 | 25.9°C | 25.2°C | 24.4°C | 26.9°C | 23.3°C | 51 mm | 78% | 5.3 m/s | 4.2 |
| 2019 | 25.8°C | 25.1°C | 24.5°C | 26.8°C | 23.5°C | 107 mm | 79% | 6.2 m/s | 3.8 |
| 2018 | 24.8°C | 24.1°C | 23.5°C | 25.6°C | 22.1°C | 73 mm | 78% | 6.5 m/s | 4.1 |
| 2017 | 23.8°C | 23.0°C | 22.2°C | 25.1°C | 21.1°C | 82 mm | 75% | 4.7 m/s | 3.7 |
| 2016 | 24.5°C | 23.9°C | 23.2°C | 25.8°C | 21.5°C | 91 mm | 79% | 5 m/s | 3.4 |
| 2015 | 25.5°C | 24.8°C | 24.1°C | 26.6°C | 23.2°C | 37 mm | 77% | 6.3 m/s | 4.1 |
| 2014 | 24.5°C | 23.6°C | 22.8°C | 26.0°C | 20.4°C | 61 mm | 75% | 5.2 m/s | 3.8 |
| 2013 | 25.2°C | 24.4°C | 23.7°C | 26.5°C | 22.4°C | 61 mm | 78% | 4.3 m/s | 4.1 |
| 2012 | 24.8°C | 24.0°C | 23.3°C | 25.9°C | 22.5°C | 55 mm | 78% | 5.8 m/s | 3.8 |
| 2011 | 23.9°C | 23.4°C | 22.8°C | 25.0°C | 21.9°C | 75 mm | 78% | 6.9 m/s | 4 |
| 2010 | 25.0°C | 24.3°C | 23.6°C | 25.8°C | 21.8°C | 202 mm | 77% | 3.7 m/s | 3.7 |
| 2009 | 24.8°C | 23.9°C | 23.0°C | 25.8°C | 22.1°C | 16 mm | 74% | 3.7 m/s | 4.3 |
| 2008 | 24.6°C | 24.1°C | 23.5°C | 25.8°C | 22.4°C | 160 mm | 80% | 5.2 m/s | 3.6 |
| 2007 | 24.8°C | 24.2°C | 23.6°C | 26.5°C | 22.7°C | 76 mm | 78% | 7.3 m/s | 3.7 |
| 2006 | 24.8°C | 24.1°C | 23.5°C | 26.0°C | 22.6°C | 38 mm | 75% | 6.2 m/s | 4 |
| 2005 | 25.0°C | 24.1°C | 23.2°C | 26.6°C | 21.9°C | 13 mm | 75% | 4.3 m/s | 4.5 |
| 2004 | 25.1°C | 24.3°C | 23.6°C | 26.0°C | 21.9°C | 84 mm | 74% | 5 m/s | 3.8 |
| 2003 | 24.6°C | 23.9°C | 23.2°C | 25.4°C | 21.5°C | 105 mm | 77% | 5.7 m/s | 3.8 |
| 2002 | 24.5°C | 23.7°C | 22.9°C | 25.6°C | 21.9°C | 21 mm | 76% | 5.5 m/s | 4.3 |
| 2001 | 24.5°C | 23.9°C | 23.3°C | 25.5°C | 22.2°C | 72 mm | 76% | 7.4 m/s | 3.9 |
| 2000 | 24.8°C | 23.9°C | 23.0°C | 26.3°C | 22.3°C | 15 mm | 75% | 4.7 m/s | 4.4 |
| 1999 | 23.9°C | 23.3°C | 22.6°C | 25.0°C | 20.5°C | 53 mm | 79% | 6.2 m/s | 3.8 |
| 1998 | 23.8°C | 23.1°C | 22.4°C | 25.1°C | 21.0°C | 35 mm | 77% | 6.4 m/s | 4 |
| 1997 | 23.6°C | 23.0°C | 22.3°C | 24.9°C | 20.6°C | 14 mm | 74% | 6.9 m/s | 3.9 |
| 1996 | 24.0°C | 23.2°C | 22.4°C | 25.5°C | 20.4°C | 76 mm | 75% | 6.3 m/s | 3.7 |
| 1995 | 25.6°C | 24.9°C | 24.1°C | 26.9°C | 20.7°C | 28 mm | 76% | 4.3 m/s | 4.1 |
| 1994 | 23.6°C | 23.0°C | 22.4°C | 24.3°C | 21.5°C | 26 mm | 71% | 6.9 m/s | 3.9 |
| 1993 | 23.8°C | 23.2°C | 22.7°C | 24.5°C | 21.8°C | 15 mm | 72% | 6.3 m/s | 3.8 |
| 1992 | 24.8°C | 24.3°C | 23.8°C | 25.8°C | 22.5°C | 58 mm | 78% | 6.3 m/s | 3.3 |
| 1991 | 24.4°C | 23.8°C | 23.2°C | 26.2°C | 21.2°C | 52 mm | 76% | 6.5 m/s | 3.6 |
| 1990 | 23.9°C | 23.3°C | 22.7°C | 24.9°C | 20.7°C | 130 mm | 78% | 6.3 m/s | 3.5 |
| 1989 | 23.9°C | 23.1°C | 22.3°C | 25.9°C | 20.7°C | 62 mm | 74% | 4.2 m/s | 4 |
| 1988 | 25.1°C | 24.4°C | 23.7°C | 26.5°C | 20.1°C | 52 mm | 76% | 5.5 m/s | 4 |
| 1987 | 24.5°C | 23.8°C | 23.2°C | 25.7°C | 20.6°C | 124 mm | 80% | 5.4 m/s | 3.3 |
| 1986 | 24.3°C | 23.6°C | 22.9°C | 25.7°C | 20.5°C | 29 mm | 76% | 5.3 m/s | 3.7 |
| 1985 | 23.5°C | 22.8°C | 22.1°C | 25.6°C | 20.2°C | 82 mm | 76% | 4.7 m/s | 3.9 |
| 1984 | 24.0°C | 23.4°C | 22.7°C | 25.1°C | 21.2°C | 75 mm | 76% | 5.3 m/s | 3.7 |
| 1983 | 23.9°C | 23.2°C | 22.5°C | 25.6°C | 20.5°C | 159 mm | 76% | 4.2 m/s | — |
| 1982 ❄️ | 23.1°C | 22.5°C | 21.9°C | 25.3°C | 20.5°C | 171 mm | 79% | 5.4 m/s | — |
| 1981 | 24.0°C | 23.3°C | 22.7°C | 25.2°C | 20.4°C | 56 mm | 79% | 5.3 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 24.6°C with lows near 23.2°C (mean 23.9°C), based on 45 years of NASA POWER data.
December averages 71 mm of rainfall in Kailua, a relatively wet time of year. The wettest on record was 234 mm in 2021.
The hottest December reached 27.1°C in 2024. The coldest dipped to 20.1°C in 1988.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.7°C. Daytime highs moved from 23.7°C to 25.5°C and overnight lows from 22.4°C to 23.9°C over the same span.
December is one of the cooler months of the year in Kailua and a relatively wet time of year, so plan for around 24.6°C daytime highs and 23.2°C at night.
Not quite — December is the 5th coolest month in Kailua, averaging 23.9°C.
For December in Kailua, pack light layers you can adjust through the day, with typical highs of 24.6°C and lows of 23.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 77% — quite humid.
Average wind speed in December is 5.5 m/s. The windiest December on record averaged 7.4 m/s (2001).
The wettest December on record was 2021 with 234 mm. On average, December sees 71 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 Kailua behaves each December, 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 December specifically, along with year-by-year records and how the month has changed over the decades.
