Hilo climate — normals and trends
Hilo (United States) has a tropical rainforest climate (Af) under the Köppen-Geiger classification. Its mean annual temperature is 21.8 °C and it receives 2,110 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is September (23.2 °C on average) and the coldest is February (20.5 °C). Rainfall peaks in March.
Hilo averages 0 frost days, 0 hot days (≥ 30 °C) and 291 rainy days per year.
Hilo has warmed by +0.9 °C between 1940 and 2025, or +0.10 °C per decade. This trend is statistically significant.
The hottest day of the period reached 29.1 °C (on 26 July 2020) and the coldest 16.2 °C (on 10 December 1973).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
HiloHawaii
- coords
- 19.73°, -155.09°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
21.8°C
Average daily high
23.4°C
Average daily low
20.6°C
Annual rainfall
2,110mm
Sunshine / day
11.2h
Mean relative humidity
82%
Average peak wind
16.4km/h
Seasonal range
2.7°C
Frost days (< 0 °C)
0 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
291 d/yr
Annual snowfall
0.0 cm
Average feels-like high
26.0 °C
Average feels-like low
22.3 °C
Average peak gust
26.8 km/h
Tropical nights (≥ 20 °C)
247 d/yr
Solar radiation
19.8 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+0.9 °C
since 1940
+0.1 °C per decade · r² = 0.33 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
29.1 °C
26 July 2020
Coldest day
16.2 °C
10 December 1973
Wettest day
279 mm
13 December 1987
Windiest day
58.7 km/h
7 August 2014
Strongest gust
85.3 km/h
1 December 1957
Hottest feels-like
35.8 °C
1 September 2015
Coldest feels-like
11.5 °C
5 March 1954
Sunniest day
13.0 h
16 June 1940
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 23.5 °C | +1.0 °C | 89 mm | -86 mm |
| Feb | 23.7 °C | +1.5 °C | 56 mm | -130 mm |
| Mar | 23.4 °C | +1.2 °C | 171 mm | -76 mm |
| Apr | 24.4 °C | +1.9 °C | 70 mm | -128 mm |
| May | 24.0 °C | +0.8 °C | 84 mm | -71 mm |
| Jun | 24.5 °C | +0.6 °C | 103 mm | -29 mm |
| Jul | 25.0 °C | +0.7 °C | 104 mm | -56 mm |
| Aug | 25.5 °C | +0.8 °C | 65 mm | -107 mm |
| Sep | 25.6 °C | +0.8 °C | 66 mm | -57 mm |
| Oct | 25.3 °C | +0.8 °C | 130 mm | -28 mm |
| Nov | 24.2 °C | +0.5 °C | 210 mm | +1 mm |
| Dec | 24.0 °C | +1.2 °C | 67 mm | -131 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Hilo?
Hilo has a tropical rainforest climate (Köppen Af). Over 1940-2025, the average annual temperature is 21.8 °C and it receives 2,110 mm of precipitation per year.
What is the hottest day ever recorded in Hilo?
The hottest day measured in Hilo between 1940 and 2025 was 26 July 2020, reaching 29.1 °C.
What is the coldest day in Hilo?
The coldest day measured in Hilo between 1940 and 2025 was 10 December 1973, at 16.2 °C.
Does it snow in Hilo?
Almost never: Hilo sees virtually no snow, with about 0 frost days per year.
Has the climate of Hilo warmed?
Yes: Hilo warmed by +0.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Hilo?
The wettest day measured in Hilo between 1940 and 2025 was 13 December 1987, with 279 mm of rain in 24 hours.
What was the windiest day in Hilo?
The windiest day measured in Hilo between 1940 and 2025 was 7 August 2014, with winds reaching 58.7 km/h.
What is the warmest month in Hilo?
The warmest month in Hilo is September (23.2 °C on average); the coldest is February (20.5 °C).
How much does it rain in Hilo?
Hilo receives on average 2,110 mm of precipitation per year, spread over about 291 rainy days.
Is it sunny in Hilo?
Hilo gets on average 11.2 hours of sunshine per day, roughly 4,088 hours per year over 1940-2025.
Are there tropical nights in Hilo?
Yes: Hilo has on average 247 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Hilo?
In Hilo, between 1940 and 2025, the highest apparent temperature reached 35.8 °C on 1 September 2015, and the lowest was 11.5 °C on 5 March 1954.
Compare Hilo with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Hilo