30-year climate normals

Honolulu County Climate and Weather Averages

Hottest month — August

85.6°

average daily high. The coldest month is February, averaging a low of 64.4°F.

Honolulu County gets 21.78" of precipitation a year, and 41% of it falls in Nov, Dec, Jan.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	78.7°	64.8°	3.18"
February	78.4°	64.4°	2.27"
March	78.8°	65.1°	2.74"
April	80.2°	66.3°	1.35"
May	81.8°	67.5°	1.64"
June	83.4°	68.9°	0.80"
July	85.0°	70.2°	0.47"
August	85.6°	70.2°	0.74"
September	84.5°	70.4°	0.92"
October	84.5°	70.3°	1.93"
November	82.1°	68.7°	2.54"
December	80.2°	66.8°	3.20"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 41% falling in the wettest three months (Nov, Dec, Jan).

January 3.18"

February 2.27"

March 2.74"

April 1.35"

May 1.64"

June 0.80"

July 0.47"

August 0.74"

September 0.92"

October 1.93"

November 2.54"

December 3.20"

Annual total 21.78"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 3,609

Heating degree days How much heating the climate demands 0

Approximate annual cooling cost At 52¢/kWh, Hawaii average $1,877

Approximate annual electric heating cost Lower where heating is gas rather than electric $0

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Honolulu County, where electricity is one line of eight.

Common questions

What is the weather like in Honolulu County?

Honolulu County averages a high of 85.6°F in August and a low of 64.4°F in February. Annual precipitation is 21.78 inches, with essentially no snow.

When is the rainy season in Honolulu County?

The wettest stretch is Nov, Dec, Jan, which accounts for 41% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Honolulu County?

The average daily high in August, the hottest month, is 85.6°F. That drives 3,609 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Honolulu County?

Effectively no. Measurable snowfall is rare in Honolulu County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station MAKAHA CTRY CLUB 800.3, HI US (USC00515758), 1.2 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, Hawaii residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.