Average Weather in August in Irwindale California, United States
Daily high temperatures are around 90°F, rarely falling below 82°F or exceeding 99°F. The highest daily average high temperature is 91°F on August 23.
Daily low temperatures are around 67°F, rarely falling below 62°F or exceeding 73°F. The highest daily average low temperature is 67°F on August 23.
For reference, on August 22, the hottest day of the year, temperatures in Irwindale typically range from 67°F to 91°F, while on December 25, the coldest day of the year, they range from 46°F to 66°F.
Average High and Low Temperature in August
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
The month of August in Irwindale experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 10% throughout the month.
The clearest day of the month is August 23, with clear, mostly clear, or partly cloudy conditions 90% of the time.
For reference, on February 22, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 44%, while on September 7, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%.
Cloud Cover Categories in August
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Irwindale, the chance of a wet day over the course of August is essentially constant, remaining around 1% throughout.
For reference, the year's highest daily chance of a wet day is 20% on February 19, and its lowest chance is 0% on July 2.
Probability of Precipitation in August
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 Irwindale is essentially constant, remaining about 0.1 inches throughout, and rarely exceeding 0.2 inches or falling below -0.0 inches.
Average Monthly Rainfall in August
Over the course of August in Irwindale, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 55 minutes, implying an average daily decrease of 1 minute, 51 seconds, and weekly decrease of 12 minutes, 57 seconds.
The shortest day of the month is August 31, with 12 hours, 54 minutes of daylight and the longest day is August 1, with 13 hours, 50 minutes of daylight.
Hours of Daylight and Twilight in August
The earliest sunrise of the month in Irwindale is 6:03 AM on August 1 and the latest sunrise is 22 minutes later at 6:24 AM on August 31.
The latest sunset is 7:52 PM on August 1 and the earliest sunset is 34 minutes earlier at 7:18 PM on August 31.
Daylight saving time is observed in Irwindale during 2018, but it neither starts nor ends during August, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:40 AM and sets 14 hours, 26 minutes later, at 8:06 PM, while on December 21, the shortest day of the year, it rises at 6:53 AM and sets 9 hours, 53 minutes later, at 4:46 PM.
Sunrise & Sunset with Twilight in August
The chance that a given day will be muggy in Irwindale is essentially constant during August, remaining around 2% throughout.
The highest chance of a muggy day during August is 3% on August 28.
For reference, on August 28, the muggiest day of the year, there are muggy conditions 3% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in August
The average hourly wind speed in Irwindale is essentially constant during August, remaining within 0.1 miles per hour of 5.3 miles per hour throughout.
For reference, on December 31, the windiest day of the year, the daily average wind speed is 8.1 miles per hour, while on September 6, the calmest day of the year, the daily average wind speed is 5.2 miles per hour.
Average Wind Speed in August
Wind Direction in August
Irwindale 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 Irwindale is essentially constant during August, remaining around 68°F throughout.
The highest average surface water temperature during August is 69°F on August 24.
Average Water Temperature in August
Temperatures in Irwindale 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
The average accumulated growing degree days in Irwindale are rapidly increasing during August, increasing by 781°F, from 3,060°F to 3,841°F, over the course of the month.
Growing Degree Days in August
The average daily incident shortwave solar energy in Irwindale is gradually decreasing during August, falling by 0.9 kWh, from 7.9 kWh to 7.1 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in August
For the purposes of this report, the geographical coordinates of Irwindale are 34.107 deg latitude, -117.935 deg longitude, and 476 ft elevation.
The topography within 2 miles of Irwindale contains only modest variations in elevation, with a maximum elevation change of 354 feet and an average elevation above sea level of 468 feet. Within 10 miles contains only modest variations in elevation (5,157 feet). Within 50 miles also contains extreme variations in elevation (10,033 feet).
The area within 2 miles of Irwindale is covered by artificial surfaces (81%) and shrubs (19%), within 10 miles by artificial surfaces (64%) and shrubs (29%), and within 50 miles by shrubs (49%) and artificial surfaces (24%).
This report illustrates the typical weather in Irwindale year round, 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 Irwindale.
For each station, the records are corrected for the elevation difference between that station and Irwindale 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 Irwindale is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Irwindale and a given station.
The stations contributing to this reconstruction are: Mount Wilson (2.8%, 19 kilometers, northwest); Fullerton Municipal Airport (37%, 26 kilometers, south); Ontario International Airport (33%, 27 kilometers, east); and Los Angeles / USC Campus Downtown (27%, 34 kilometers, west).
Time zones for aiports and weather stations are provided by AskGeo.com .