Average Weather in September in Spring Valley Lake California, United States
Daily high temperatures decrease by 9°F, from 94°F to 85°F, rarely falling below 74°F or exceeding 100°F.
Daily low temperatures decrease by 8°F, from 65°F to 56°F, rarely falling below 48°F or exceeding 71°F.
For reference, on July 26, the hottest day of the year, temperatures in Spring Valley Lake typically range from 68°F to 97°F, while on December 25, the coldest day of the year, they range from 34°F to 57°F.
Average High and Low Temperature in September
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on September. 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 September
The month of September in Spring Valley Lake experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 12% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 11% on September 7.
The clearest day of the month is September 7, with clear, mostly clear, or partly cloudy conditions 89% of the time.
For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 46%, while on September 7, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 89%.
Cloud Cover Categories in September
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Spring Valley Lake, the chance of a wet day over the course of September is essentially constant, remaining around 4% throughout.
For reference, the year's highest daily chance of a wet day is 17% on February 21, and its lowest chance is 1% on June 15.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Spring Valley Lake is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.8 inches or falling below -0.0 inches.
The lowest average 31-day accumulation is 0.2 inches on September 9.
Average Monthly Rainfall in September
Over the course of September in Spring Valley Lake, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1 hour, 1 minute, implying an average daily decrease of 2 minutes, 7 seconds, and weekly decrease of 14 minutes, 50 seconds.
The shortest day of the month is September 30, with 11 hours, 51 minutes of daylight and the longest day is September 1, with 12 hours, 53 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Spring Valley Lake is 6:22 AM on September 1 and the latest sunrise is 21 minutes later at 6:43 AM on September 30.
The latest sunset is 7:15 PM on September 1 and the earliest sunset is 41 minutes earlier at 6:34 PM on September 30.
Daylight saving time is observed in Spring Valley Lake during 2018, but it neither starts nor ends during September, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:36 AM and sets 14 hours, 28 minutes later, at 8:04 PM, while on December 21, the shortest day of the year, it rises at 6:51 AM and sets 9 hours, 51 minutes later, at 4:42 PM.
Sunrise & Sunset with Twilight in September
The chance that a given day will be muggy in Spring Valley Lake is essentially constant during September, remaining around 0% throughout.
For reference, on August 22, the muggiest day of the year, there are muggy conditions 1% 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 September
The average hourly wind speed in Spring Valley Lake is essentially constant during September, remaining within 0.1 miles per hour of 6.9 miles per hour throughout.
For reference, on May 3, the windiest day of the year, the daily average wind speed is 9.0 miles per hour, while on September 9, the calmest day of the year, the daily average wind speed is 6.8 miles per hour.
The lowest daily average wind speed during September is 6.8 miles per hour on September 9.
Average Wind Speed in September
Wind Direction in September
Spring Valley Lake 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 Spring Valley Lake is essentially constant during September, remaining within 1°F of 68°F throughout.
Average Water Temperature in September
The growing season in Spring Valley Lake typically lasts for 8.7 months (266 days), from around March 1 to around November 22, rarely starting before January 27 or after April 5, and rarely ending before November 1 or after December 14.
The month of September in Spring Valley Lake is reliably fully within the growing season.
Time Spent in Various Temperature Bands and the Growing Season in September
The average accumulated growing degree days in Spring Valley Lake are rapidly increasing during September, increasing by 680°F, from 3,704°F to 4,385°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Spring Valley Lake is decreasing during September, falling by 1.1 kWh, from 7.0 kWh to 5.9 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in September
For the purposes of this report, the geographical coordinates of Spring Valley Lake are 34.494 deg latitude, -117.268 deg longitude, and 2,894 ft elevation.
The topography within 2 miles of Spring Valley Lake contains only modest variations in elevation, with a maximum elevation change of 272 feet and an average elevation above sea level of 2,851 feet. Within 10 miles contains only modest variations in elevation (2,339 feet). Within 50 miles contains large variations in elevation (11,270 feet).
The area within 2 miles of Spring Valley Lake is covered by shrubs (91%), within 10 miles by shrubs (97%), and within 50 miles by shrubs (80%).
This report illustrates the typical weather in Spring Valley Lake 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 Spring Valley Lake.
For each station, the records are corrected for the elevation difference between that station and Spring Valley Lake 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 Spring Valley Lake is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Spring Valley Lake and a given station.
The stations contributing to this reconstruction are: Southern California Logistics Airport (84%, 14 kilometers, northwest); San Bernardino International Airport (8%, 44 kilometers, south); and Barstow Daggett County Airport (8%, 60 kilometers, northeast).
Time zones for aiports and weather stations are provided by AskGeo.com .