Hilo in Summer
In summer (June, July and August), Hilo sees average daytime highs around 76°F and overnight lows near 71°F, with 17.1 in of rain over about 76 wet days across the season. It is the warmest season of the year and the driest season of the year.
Across summer, daytime highs hold fairly steady around 76°F. The sky is clear or mostly clear about 28% of the time across summer, and the air most often feels muggy.
Summer is Hilo's weakest season of the year to visit on our travel score. Hilo has little temperature swing across the year, so its calendar seasons blur — the season framing matters less here than for a place with four distinct seasons. For the whole year in context, see Hilo's year-round climate.
- Avg daytime high
- 76°F
- warmest season of the year
- Avg overnight low
- 71°F
- Rainfall
- 17.1 in
- 76 wet days
- Avg wind
- 6 mph
- Travel score
- 4.7
- weakest season of the year
- Months
- Jun · Jul · Aug
Temperature in Hilo in Summer
Across summer, daytime highs hold fairly steady around 76°F.
A typical summer day in Hilo reaches about 76°F and drops to 71°F overnight. The warmest of the three months is August, the coolest June.
Hilo weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 73° / 67° | 5.8 | 16.8 | 10.9 | 6.0 |
| Feb | 72° / 67° | 6.6 | 17.2 | 11.3 | 5.5 |
| Mar | 72° / 67° | 9.1 | 23.5 | 11.9 | 4.7 |
| Apr | 73° / 68° | 7.1 | 24.8 | 12.4 | 4.5 |
| May | 74° / 69° | 5.7 | 23.7 | 12.9 | 4.9 |
| Jun | 75° / 70° | 4.7 | 24.1 | 13.2 | 4.8 |
| Jul | 76° / 71° | 5.7 | 25.8 | 13.1 | 4.6 |
| Aug | 77° / 72° | 6.7 | 25.6 | 12.7 | 4.6 |
| Sep | 77° / 72° | 4.5 | 22 | 12.1 | 5.1 |
| Oct | 77° / 71° | 5.4 | 23 | 11.5 | 5.0 |
| Nov | 75° / 70° | 7.5 | 23.2 | 11.1 | 4.8 |
| Dec | 73° / 68° | 7.9 | 22.2 | 10.8 | 5.1 |
Cloud cover in Summer
The sky is clear or mostly clear about 28% of the time across summer.
Chance of precipitation in Summer
Hilo gets around 17.1 in of rain over 76 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 6 mph across summer.
Sunrise & sunset in Summer
Daylight runs from about 13 h 06 min in early June to 12 h 24 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 6.5 kWh/m².
Hazard calendar for Hilo
In summer, Hilo overlaps its pacific hurricane season. The full year is below, with each hazard's peak months called out.
Hilo sits in the eastern Pacific hurricane zone; the season peaks August–September.
Is summer a good time to visit Hilo?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Hilo for sightseeing.
What to pack for Hilo in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Hilo sees daytime highs around 76°F and nights near 71°F. Pack rain gear and sun protection. Worth having: light clothes. About 76 days see rain.
Sea temperature near Hilo in Summer
The nearest coast averages about 79°F across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 11 mi away) is warmest in September at about 80°F and coldest in March near 75°F.
The water stays above 68°F all year — warm enough for a swim any month.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 76 | 75 | 75 | 76 | 77 | 78 | 79 | 79 | 80 | 80 | 78 | 77 |
| Comfort | Warm | Warm | Warm | Warm | Warm | Warm | Warm | Warm | Warm | Warm | Warm | Warm |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 76 | Warm |
| Feb | 75 | Warm |
| Mar | 75 | Warm |
| Apr | 76 | Warm |
| May | 77 | Warm |
| Jun | 78 | Warm |
| Jul | 79 | Warm |
| Aug | 79 | Warm |
| Sep | 80 | Warm |
| Oct | 80 | Warm |
| Nov | 78 | Warm |
| Dec | 77 | Warm |
UV index in Hilo in Summer
Clear-sky midday UV across summer averages around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Hilo peaks around August 15 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 7 (high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 8 | 10 | 12 | 14 | 11 | 13 | 13 | 14 | 13 | 10 | 8 | 7 |
| Level | Very high | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | High |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 8 | Very high |
| Feb | 10 | Very high |
| Mar | 12 | Extreme |
| Apr | 14 | Extreme |
| May | 11 | Extreme |
| Jun | 13 | Extreme |
| Jul | 13 | Extreme |
| Aug | 14 | Extreme |
| Sep | 13 | Extreme |
| Oct | 10 | Extreme |
| Nov | 8 | Very high |
| Dec | 7 | High |
Air quality in Hilo in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in Hilo is worst in January — around 28 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (July, 16 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 28 | 27 | 26 | 23 | 22 | 19 | 16 | 18 | 21 | 25 | 22 | 24 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 28 | Moderate |
| Feb | 27 | Moderate |
| Mar | 26 | Moderate |
| Apr | 23 | Moderate |
| May | 22 | Moderate |
| Jun | 19 | Moderate |
| Jul | 16 | Moderate |
| Aug | 18 | Moderate |
| Sep | 21 | Moderate |
| Oct | 25 | Moderate |
| Nov | 22 | Moderate |
| Dec | 24 | Moderate |
Where is Hilo?
Hilo sits at 19.7°N, 155.1°W, 59 ft above sea level, in United States. The nearest listed city is Kīhei, 113 mi away.
Topography around Hilo
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Hilo.
Within 2 miles, the terrain around Hilo has only modest variations in elevation — a maximum elevation change of 774 ft around an average of 197 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 3,606 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 13,750 ft.
The land around Hilo is covered by trees (34%), water (29%) and grassland (22%) within 2 miles, trees (42%) and water (29%) within 10 miles, and water (49%) and grassland (20%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Hilo (19.7299°, -155.0907°, elevation 59 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.