August is one of the warmer months of the year in Hilo, with average highs near 25.1°C and lows around 21°C (mean 23.1°C). It is about average for rainfall, averaging 152 mm of rainfall and 82% relative humidity across the period.
August is one of the warmer months of the year in Hilo. Across 45 years of records, the warmest August in Hilo was 2015 — when the month averaged 24.4°C — while the coldest were 1983 and 2010 at 21.8°C. Typical August days reach 25.1°C with nights near 21°C. The long-term August temperature trend is broadly flat.
August is about average for rainfall in Hilo, averaging 152 mm of rainfall. The wettest August on record was 1983 with 1783 mm, while the driest was 1993 at 2 mm.
Relative humidity in Hilo during August averages 82%. The most humid Augusts were 1982 and 2015 at 86%, and the least humid was 1996 at 75%.
August receives about 6 kWh/m²/day of solar energy in Hilo. The sunniest August was 2009 at 6.6 kWh/m²/day, and the cloudiest was 2018 at 5.4.
Average wind speed in Hilo during August is 4.2 m/s. The windiest August was 1992 at 4.9 m/s, while the calmest was 2019 at 3.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 22.8°C | 23.5°C | 22.8°C | 23.1°C | 23.2°C | +0.4°C |
| Avg High | 24.9°C | 25.8°C | 24.7°C | 25.0°C | 25.3°C | +0.4°C |
| Avg Low | 20.8°C | 21.2°C | 20.9°C | 21.2°C | 21.1°C | +0.3°C |
| Avg Rain | 343 mm | 9 mm | 187 mm | 146 mm | 57 mm | -285 mm |
August temperatures in Hilo have risen by about 0.6°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 18.9°C (1999) to a record high of 28.8°C (1993).
Rainfall in August is about average for rainfall, averaging 152 mm, with a wettest year of 1783 mm.
A good time to visit Hilo
August is a good time to visit Hilo, with days averaging 25.1°C and nights around 21°C (mean 23.1°C, warmer than Hilo's yearly average) and higher rainfall. June and May are marginally more temperate, but August still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 25.6°C | 23.4°C | 21.2°C | 26.6°C | 20.4°C | 80 mm | 81% | 3.9 m/s | 6.2 |
| 2024 | 25.4°C | 23.3°C | 21.3°C | 26.9°C | 19.6°C | 88 mm | 84% | 4.2 m/s | 6.3 |
| 2023 | 24.8°C | 22.9°C | 20.9°C | 25.7°C | 19.9°C | 61 mm | 82% | 4.4 m/s | 6.4 |
| 2022 | 25.4°C | 23.2°C | 21.0°C | 26.7°C | 20.0°C | 52 mm | 81% | 3.8 m/s | 6.1 |
| 2021 | 25.4°C | 23.1°C | 20.9°C | 26.9°C | 20.3°C | 36 mm | 80% | 4.2 m/s | 6.4 |
| 2020 | 25.4°C | 23.2°C | 21.1°C | 26.3°C | 20.1°C | 25 mm | 81% | 4 m/s | 6.4 |
| 2019 | 26.2°C | 24.1°C | 22.0°C | 27.5°C | 21.0°C | 126 mm | 84% | 3.4 m/s | 6.1 |
| 2018 | 25.3°C | 23.6°C | 22.0°C | 26.4°C | 20.9°C | 179 mm | 86% | 4.3 m/s | 5.4 |
| 2017 | 25.4°C | 23.4°C | 21.3°C | 26.1°C | 20.4°C | 58 mm | 83% | 3.9 m/s | 6.1 |
| 2016 | 25.4°C | 23.6°C | 21.7°C | 26.6°C | 21.0°C | 233 mm | 86% | 4.1 m/s | 5.8 |
| 2015 🔥 | 26.2°C | 24.4°C | 22.6°C | 27.6°C | 21.8°C | 202 mm | 86% | 3.7 m/s | 5.7 |
| 2014 | 25.1°C | 23.1°C | 21.2°C | 26.7°C | 20.2°C | 166 mm | 84% | 4 m/s | 6 |
| 2013 | 24.8°C | 22.8°C | 20.8°C | 26.0°C | 20.1°C | 134 mm | 82% | 4.2 m/s | 6.3 |
| 2012 | 24.0°C | 22.0°C | 20.1°C | 25.0°C | 19.0°C | 83 mm | 82% | 4.3 m/s | 6 |
| 2011 | 23.8°C | 22.0°C | 20.3°C | 25.4°C | 19.4°C | 177 mm | 84% | 4.4 m/s | 6.2 |
| 2010 | 23.7°C | 21.8°C | 19.9°C | 24.4°C | 19.4°C | 107 mm | 83% | 4.4 m/s | 6.3 |
| 2009 | 24.8°C | 23.0°C | 21.2°C | 27.9°C | 20.3°C | 209 mm | 85% | 4.4 m/s | 6.6 |
| 2008 | 24.0°C | 22.1°C | 20.3°C | 25.2°C | 19.4°C | 191 mm | 83% | 4.3 m/s | 6.4 |
| 2007 | 24.4°C | 22.5°C | 20.6°C | 25.9°C | 19.8°C | 221 mm | 83% | 4.3 m/s | 6 |
| 2006 | 24.7°C | 22.9°C | 21.0°C | 26.6°C | 20.1°C | 212 mm | 84% | 4.3 m/s | 6.1 |
| 2005 | 24.6°C | 22.7°C | 20.7°C | 25.8°C | 19.8°C | 252 mm | 83% | 4.3 m/s | 6 |
| 2004 | 25.0°C | 23.0°C | 21.1°C | 26.5°C | 20.3°C | 186 mm | 83% | 4.1 m/s | 6.3 |
| 2003 | 24.7°C | 22.8°C | 21.0°C | 26.1°C | 19.9°C | 185 mm | 84% | 4.5 m/s | 6.2 |
| 2002 | 24.4°C | 22.7°C | 21.0°C | 25.4°C | 19.9°C | 293 mm | 85% | 4.2 m/s | 5.5 |
| 2001 | 25.2°C | 23.0°C | 20.8°C | 26.4°C | 19.9°C | 118 mm | 81% | 4.4 m/s | 6.5 |
| 2000 | 25.3°C | 23.2°C | 21.0°C | 26.6°C | 20.3°C | 4 mm | 78% | 4.8 m/s | 6.1 |
| 1999 | 24.5°C | 22.3°C | 20.0°C | 25.6°C | 18.9°C | 6 mm | 78% | 4.8 m/s | 6.3 |
| 1998 | 25.5°C | 23.1°C | 20.8°C | 27.5°C | 20.1°C | 3 mm | 77% | 4.8 m/s | 6 |
| 1997 | 26.5°C | 23.9°C | 21.3°C | 27.7°C | 20.3°C | 3 mm | 76% | 4.3 m/s | 6 |
| 1996 | 26.6°C | 24.0°C | 21.3°C | 27.9°C | 20.4°C | 5 mm | 75% | 4.1 m/s | 6.1 |
| 1995 | 25.7°C | 23.4°C | 21.1°C | 26.7°C | 20.2°C | 4 mm | 76% | 4.8 m/s | 5.9 |
| 1994 | 26.3°C | 24.0°C | 21.7°C | 27.6°C | 20.9°C | 6 mm | 77% | 4.7 m/s | 6 |
| 1993 | 26.3°C | 23.9°C | 21.6°C | 28.8°C | 20.3°C | 2 mm | 77% | 4.4 m/s | 5.9 |
| 1992 | 25.7°C | 23.8°C | 21.8°C | 27.6°C | 20.5°C | 11 mm | 79% | 4.9 m/s | 5.7 |
| 1991 | 25.1°C | 23.1°C | 21.0°C | 26.3°C | 20.1°C | 22 mm | 82% | 4.4 m/s | 5.7 |
| 1990 | 25.4°C | 23.3°C | 21.3°C | 27.1°C | 20.3°C | 30 mm | 82% | 4.3 m/s | 5.6 |
| 1989 | 25.2°C | 23.0°C | 20.7°C | 26.3°C | 20.0°C | 19 mm | 78% | 4.3 m/s | 5.7 |
| 1988 | 25.1°C | 22.9°C | 20.8°C | 26.6°C | 19.9°C | 13 mm | 79% | 4.4 m/s | 5.8 |
| 1987 | 25.3°C | 23.1°C | 20.9°C | 26.9°C | 20.0°C | 65 mm | 80% | 3.8 m/s | 6 |
| 1986 | 25.7°C | 23.6°C | 21.5°C | 26.7°C | 20.7°C | 56 mm | 83% | 3.8 m/s | 6 |
| 1985 | 24.6°C | 22.5°C | 20.5°C | 26.2°C | 19.6°C | 295 mm | 84% | 4.1 m/s | 6.1 |
| 1984 | 24.1°C | 22.1°C | 20.0°C | 25.0°C | 19.5°C | 105 mm | 82% | 3.9 m/s | 5.8 |
| 1983 ❄️ 🌧️ | 23.6°C | 21.8°C | 20.1°C | 25.1°C | 19.2°C | 1783 mm | 85% | 4.3 m/s | — |
| 1982 | 24.8°C | 23.1°C | 21.5°C | 26.4°C | 20.4°C | 726 mm | 86% | 4.4 m/s | — |
| 1981 | 25.6°C | 23.3°C | 21.0°C | 26.7°C | 20.1°C | 21 mm | 79% | 3.9 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 25.1°C with lows near 21°C (mean 23.1°C), based on 45 years of NASA POWER data.
August averages 152 mm of rainfall in Hilo, about average for rainfall. The wettest on record was 1783 mm in 1983.
The hottest August reached 28.8°C in 1993. The coldest dipped to 18.9°C in 1999.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.6°C. Daytime highs moved from 24.5°C to 25.3°C and overnight lows from 20.6°C to 21.1°C over the same span.
August is one of the warmer months of the year in Hilo and about average for rainfall, so plan for around 25.1°C daytime highs and 21°C at night.
Not quite — August is the 11th coolest month in Hilo, averaging 23.1°C.
For August in Hilo, pack light layers you can adjust through the day, with typical highs of 25.1°C and lows of 21°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 82% — quite humid.
Average wind speed in August is 4.2 m/s. The windiest August on record averaged 4.9 m/s (1992).
The wettest August on record was 1983 with 1783 mm. On average, August sees 152 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 Hilo behaves each August, 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 August specifically, along with year-by-year records and how the month has changed over the decades.
