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August Weather in Waimalu Hawaii, United States

Daily high temperatures are around 85°F, rarely falling below 83°F or exceeding 87°F. The highest daily average high temperature is 86°F on August 26.

Daily low temperatures are around 73°F, rarely falling below 71°F or exceeding 75°F. The highest daily average low temperature is 73°F on August 10.

For reference, on August 22, the hottest day of the year, temperatures in Waimalu typically range from 73°F to 86°F, while on January 26, the coldest day of the year, they range from 66°F to 78°F.

Average High and Low Temperature in August in Waimalu

Average High and Low Temperature in August in WaimaluAug112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313170°F70°F72°F72°F74°F74°F76°F76°F78°F78°F80°F80°F82°F82°F84°F84°F86°F86°F88°F88°F90°F90°FJulSepAug 2286°FAug 2286°F73°F73°FAug 185°FAug 185°F73°F73°FAug 3186°FAug 3186°F73°F73°FAug 1185°FAug 1185°F73°F73°F
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on August. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in August in Waimalu

Average Hourly Temperature in August in WaimaluAug112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMJulSepcomfortablewarmwarmcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Bayamon, Puerto Rico (5,886 miles away) and Port-Vila, Vanuatu (3,543 miles) are the far-away foreign places with temperatures most similar to Waimalu (view comparison).

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The month of August in Waimalu experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 27% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 25% on August 13.

The clearest day of the month is August 13, with clear, mostly clear, or partly cloudy conditions 75% of the time.

For reference, on October 30, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 41%, while on January 18, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 79%.

Cloud Cover Categories in August in Waimalu

Cloud Cover Categories in August in WaimaluAug11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JulSepOct 3058%Oct 3058%Aug 174%Aug 174%Aug 3172%Aug 3172%Aug 1174%Aug 1174%Aug 2174%Aug 2174%clearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Waimalu, the chance of a wet day over the course of August is essentially constant, remaining around 9% throughout.

For reference, the year's highest daily chance of a wet day is 25% on January 11, and its lowest chance is 7% on June 19.

Probability of Precipitation in August in Waimalu

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during August in Waimalu is essentially constant, remaining about 0.9 inches throughout, and rarely exceeding 2.3 inches.

Average Monthly Rainfall in August in Waimalu

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.

Over the course of August in Waimalu, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 32 minutes, implying an average daily decrease of 1 minute, 4 seconds, and weekly decrease of 7 minutes, 29 seconds.

The shortest day of the month is August 31, with 12 hours, 33 minutes of daylight and the longest day is August 1, with 13 hours, 5 minutes of daylight.

Hours of Daylight and Twilight in August in Waimalu

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise of the month in Waimalu is 6:05 AM on August 1 and the latest sunrise is 10 minutes later at 6:15 AM on August 31.

The latest sunset is 7:10 PM on August 1 and the earliest sunset is 22 minutes earlier at 6:48 PM on August 31.

Daylight saving time is not observed in Waimalu during 2024.

For reference, on June 20, the longest day of the year, the Sun rises at 5:50 AM and sets 13 hours, 26 minutes later, at 7:16 PM, while on December 21, the shortest day of the year, it rises at 7:05 AM and sets 10 hours, 50 minutes later, at 5:55 PM.

Sunrise & Sunset with Twilight in August in Waimalu

The solar day over the course of August. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in August in Waimalu

Solar Elevation and Azimuth in August in WaimaluAug112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMJulSep001010202020303040405050506060707080800001010202030303040405050606060707080
northeastsouthwest
Solar elevation and azimuth over the course of August 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for August 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

Moon Rise, Set & Phases in August in Waimalu

Moon Rise, Set & Phases in August in WaimaluAug112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMJulSepJul 512:58 PMJul 512:58 PMJul 2112:18 AMJul 2112:18 AMAug 41:14 AMAug 41:14 AMAug 198:26 AMAug 198:26 AMSep 23:56 PMSep 23:56 PMSep 174:35 PMSep 174:35 PM5:33 AM5:33 AM7:40 PM7:40 PM7:13 PM7:13 PM6:16 AM6:16 AM6:19 AM6:19 AM7:46 PM7:46 PM6:40 PM6:40 PM6:08 AM6:08 AM5:59 AM5:59 AM6:53 PM6:53 PM6:34 PM6:34 PM7:00 AM7:00 AM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.
Aug 2024IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
7%3:25 AMENE5:34 PMWNW-10:30 AMN241,211 mi
2
3%4:24 AMENE6:23 PMWNW-11:25 AMN243,417 mi
3
0%5:22 AMENE7:07 PMWNW-12:17 PMN245,536 mi
4
0%6:19 AMENE7:46 PMWNW-1:05 PMS247,502 mi
5
2%7:13 AMENE8:20 PMWNW-1:48 PMS249,228 mi
6
6%8:04 AME8:51 PMW-2:29 PMS250,606 mi
7
12%8:53 AME9:21 PMW-3:08 PMS251,515 mi
8
19%9:42 AME9:51 PMW-3:47 PMS251,839 mi
9
27%10:30 AME10:21 PMW-4:26 PMS251,474 mi
10
36%11:19 AMESE10:53 PMWSW-5:06 PMS250,348 mi
11
45%12:11 PMESE11:29 PMWSW-5:49 PMS248,440 mi
12
50%1:05 PMESE--6:37 PMS245,786 mi
13
66%-12:09 AMWSW2:02 PMESE7:29 PMS242,500 mi
14
76%-12:56 AMWSW3:02 PMESE8:25 PMS238,773 mi
15
85%-1:49 AMWSW4:01 PMESE9:26 PMS234,874 mi
16
92%-2:50 AMWSW4:59 PMESE10:27 PMS231,134 mi
17
97%-3:55 AMWSW5:52 PMESE11:27 PMS227,899 mi
18
99%-5:02 AMWSW6:40 PMESE--
19
100%-6:08 AMWSW7:23 PMESE12:24 AMS225,483 mi
20
99%-7:13 AMW8:04 PME1:18 AMS224,104 mi
21
96%-8:16 AMW8:42 PME2:09 AMS223,859 mi
22
89%-9:19 AMW9:21 PME2:59 AMS224,704 mi
23
80%-10:21 AMWNW10:01 PMENE3:49 AMS226,482 mi
24
70%-11:24 AMWNW10:44 PMENE4:40 AMS228,957 mi
25
50%-12:28 PMWNW11:31 PMENE5:34 AMN231,862 mi
26
47%-1:32 PMWNW-6:30 AMN234,948 mi
27
36%12:23 AMENE2:33 PMWNW-7:27 AMN238,007 mi
28
26%1:19 AMENE3:30 PMWNW-8:25 AMN240,892 mi
29
17%2:18 AMENE4:21 PMWNW-9:21 AMN243,514 mi
30
10%3:16 AMENE5:06 PMWNW-10:13 AMN245,828 mi
31
5%4:13 AMENE5:46 PMWNW-11:02 AMS247,820 mi

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The chance that a given day will be muggy in Waimalu is gradually increasing during August, rising from 74% to 79% over the course of the month.

For reference, on September 22, the muggiest day of the year, there are muggy conditions 82% of the time, while on March 8, the least muggy day of the year, there are muggy conditions 19% of the time.

Humidity Comfort Levels in August in Waimalu

Humidity Comfort Levels in August in WaimaluAug11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%JulSepAug 174%Aug 174%Aug 3179%Aug 3179%Aug 1177%Aug 1177%Aug 2177%Aug 2177%oppressiveoppressivemuggymuggyhumidhumid
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Waimalu is decreasing during August, decreasing from 16.2 miles per hour to 14.8 miles per hour over the course of the month.

For reference, on July 2, the windiest day of the year, the daily average wind speed is 16.7 miles per hour, while on January 10, the calmest day of the year, the daily average wind speed is 12.3 miles per hour.

Average Wind Speed in August in Waimalu

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The hourly average wind direction in Waimalu throughout August is predominantly from the east, with a peak proportion of 97% on August 1.

Wind Direction in August in Waimalu

Wind Direction in August in WaimaluAug11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%JulSepeast
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Waimalu is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature in Waimalu is essentially constant during August, remaining around 80°F throughout.

Average Water Temperature in August in Waimalu

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

Temperatures in Waimalu are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Time Spent in Various Temperature Bands and the Growing Season in August in Waimalu

Time Spent in Various Temperature Bands and the Growing Season in August in WaimaluAug11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JulSep100%Aug 16100%Aug 16100%Jul 2100%Jul 2comfortablewarmhot
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days in Waimalu are rapidly increasing during August, increasing by 857°F, from 5,101°F to 5,958°F, over the course of the month.

Growing Degree Days in August in Waimalu

Growing Degree Days in August in WaimaluAug11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031315,000°F5,000°F5,200°F5,200°F5,400°F5,400°F5,600°F5,600°F5,800°F5,800°F6,000°F6,000°F6,200°F6,200°FJulSepAug 15,101°FAug 15,101°FAug 315,958°FAug 315,958°FAug 115,386°FAug 115,386°FAug 215,674°FAug 215,674°F
The average growing degree days accumulated over the course of August, with 25th to 75th and 10th to 90th percentile bands.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy in Waimalu is essentially constant during August, remaining within 0.2 kWh of 7.2 kWh throughout.

Average Daily Incident Shortwave Solar Energy in August in Waimalu

Average Daily Incident Shortwave Solar Energy in August in WaimaluAug11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhJulSepAug 17.4 kWhAug 17.4 kWhAug 317.0 kWhAug 317.0 kWhAug 117.3 kWhAug 117.3 kWhAug 217.2 kWhAug 217.2 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

For the purposes of this report, the geographical coordinates of Waimalu are 21.405 deg latitude, -157.943 deg longitude, and 397 ft elevation.

The topography within 2 miles of Waimalu contains very significant variations in elevation, with a maximum elevation change of 1,175 feet and an average elevation above sea level of 388 feet. Within 10 miles contains very significant variations in elevation (2,884 feet). Within 50 miles contains large variations in elevation (4,121 feet).

The area within 2 miles of Waimalu is covered by trees (51%) and artificial surfaces (45%), within 10 miles by trees (39%) and artificial surfaces (27%), and within 50 miles by water (92%).

This report illustrates the typical weather in Waimalu, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Waimalu.

For each station, the records are corrected for the elevation difference between that station and Waimalu according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Waimalu is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Waimalu and a given station.

The stations contributing to this reconstruction are:

To get a sense of how much these sources agree with each other, you can view a comparison of Waimalu and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

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