30-year climate normals

Kauai County Climate and Weather Averages

Hottest month — August

87.5°

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

Kauai County gets 17.84" of precipitation a year, and 45% of it falls in Dec, Jan, Feb.

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	79.1°	64.9°	1.92"
February	79.2°	64.4°	2.64"
March	80.5°	65.5°	1.66"
April	82.2°	66.6°	0.60"
May	83.6°	68.6°	1.19"
June	85.7°	70.5°	0.60"
July	86.5°	71.2°	0.29"
August	87.5°	72.7°	0.27"
September	87.2°	72.2°	0.78"
October	86.0°	71.2°	1.82"
November	83.5°	68.7°	2.62"
December	81.6°	67.0°	3.45"

Rainfall by month

Kauai County has a distinct wet season. 45% of the year's precipitation arrives in Dec, Jan, Feb.

January 1.92"

February 2.64"

March 1.66"

April 0.60"

May 1.19"

June 0.60"

July 0.29"

August 0.27"

September 0.78"

October 1.82"

November 2.62"

December 3.45"

Annual total 17.84"

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 4,056

Heating degree days How much heating the climate demands 0

Approximate annual cooling cost At 52¢/kWh, Hawaii average $2,109

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 Kauai County, where electricity is one line of eight.

Common questions

What is the weather like in Kauai County?

Kauai County averages a high of 87.5°F in August and a low of 64.4°F in February. Annual precipitation is 17.84 inches, with essentially no snow.

When is the rainy season in Kauai County?

The wettest stretch is Dec, Jan, Feb, which accounts for 45% of the year's precipitation. That is a pronounced wet season rather than rain spread evenly through the year.

How hot does it get in Kauai County?

The average daily high in August, the hottest month, is 87.5°F. That drives 4,056 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Kauai County?

Effectively no. Measurable snowfall is rare in Kauai County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station BARKING SANDS, HI US (USW00022501), 5.2 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.