Average Weather in May in Riverside California, United States
Daily high temperatures increase by 3°F, from 79°F to 82°F, rarely falling below 67°F or exceeding 93°F.
Daily low temperatures increase by 4°F, from 54°F to 57°F, rarely falling below 47°F or exceeding 62°F.
For reference, on August 23, the hottest day of the year, temperatures in Riverside typically range from 65°F to 94°F, while on December 27, the coldest day of the year, they range from 43°F to 67°F.
Average High and Low Temperature in May
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on May. 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 May
The month of May in Riverside experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 26% to 20%.
The clearest day of the month is May 31, with clear, mostly clear, or partly cloudy conditions 80% of the time.
For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 45%, while on September 7, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 90%.
Cloud Cover Categories in May
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Riverside, the chance of a wet day over the course of May is gradually decreasing, starting the month at 5% and ending it at 1%.
For reference, the year's highest daily chance of a wet day is 20% on February 20, and its lowest chance is 0% on June 25.
Probability of Precipitation in May
The average sliding 31-day rainfall during May in Riverside is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.9 inches.
Average Monthly Rainfall in May
Over the course of May in Riverside, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 42 minutes, implying an average daily increase of 1 minute, 25 seconds, and weekly increase of 9 minutes, 53 seconds.
The shortest day of the month is May 1, with 13 hours, 33 minutes of daylight and the longest day is May 31, with 14 hours, 15 minutes of daylight.
Hours of Daylight and Twilight in May
The latest sunrise of the month in Riverside is 6:00 AM on May 1 and the earliest sunrise is 21 minutes earlier at 5:39 AM on May 31.
The earliest sunset is 7:33 PM on May 1 and the latest sunset is 22 minutes later at 7:55 PM on May 31.
Daylight saving time is observed in Riverside during 2018, but it neither starts nor ends during May, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:38 AM and sets 14 hours, 25 minutes later, at 8:03 PM, while on December 21, the shortest day of the year, it rises at 6:50 AM and sets 9 hours, 54 minutes later, at 4:44 PM.
Sunrise & Sunset with Twilight in May
The chance that a given day will be muggy in Riverside is essentially constant during May, remaining around 0% throughout.
For reference, on August 12, the muggiest day of the year, there are muggy conditions 6% of the time, while on October 31, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in May
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The average hourly wind speed in Riverside is essentially constant during May, remaining within 0.2 miles per hour of 6.4 miles per hour throughout.
For reference, on December 31, the windiest day of the year, the daily average wind speed is 7.2 miles per hour, while on September 9, the calmest day of the year, the daily average wind speed is 5.1 miles per hour.
Average Wind Speed in May
Wind Direction in May
Riverside 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 Riverside is gradually increasing during May, rising by 2°F, from 61°F to 64°F, over the course of the month.
Average Water Temperature in May
While it does not do so every year, freezing temperatures are seen in Riverside over some winters. The day least likely to be in the growing season is January 4, with a 74% chance.
Time Spent in Various Temperature Bands and the Growing Season in May
The average accumulated growing degree days in Riverside are rapidly increasing during May, increasing by 479°F, from 1,071°F to 1,550°F, over the course of the month.
Growing Degree Days in May
The average daily incident shortwave solar energy in Riverside is gradually increasing during May, rising by 0.7 kWh, from 7.7 kWh to 8.4 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in May
For the purposes of this report, the geographical coordinates of Riverside are 33.953 deg latitude, -117.396 deg longitude, and 846 ft elevation.
The topography within 2 miles of Riverside contains only modest variations in elevation, with a maximum elevation change of 472 feet and an average elevation above sea level of 849 feet. Within 10 miles contains only modest variations in elevation (2,516 feet). Within 50 miles contains large variations in elevation (11,503 feet).
The area within 2 miles of Riverside is covered by artificial surfaces (97%), within 10 miles by shrubs (56%) and artificial surfaces (32%), and within 50 miles by shrubs (58%) and artificial surfaces (18%).
This report illustrates the typical weather in Riverside 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Riverside.
For each station, the records are corrected for the elevation difference between that station and Riverside 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 Riverside is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Riverside and a given station.
The stations contributing to this reconstruction are: Riverside Municipal Airport (88%, 4.0 kilometers, west); March Air Reserve Base (6%, 15 kilometers, southeast); and San Bernardino International Airport (6%, 22 kilometers, northeast).
Time zones for aiports and weather stations are provided by AskGeo.com .