Average Weather in October in Spring Valley California, United States
Daily high temperatures decrease by 5°F, from 79°F to 75°F, rarely falling below 66°F or exceeding 90°F.
Daily low temperatures decrease by 7°F, from 60°F to 54°F, rarely falling below 48°F or exceeding 65°F.
For reference, on August 24, the hottest day of the year, temperatures in Spring Valley typically range from 65°F to 83°F, while on December 27, the coldest day of the year, they range from 44°F to 66°F.
Average High and Low Temperature in October
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on October. 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 October
The month of October in Spring Valley experiences increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 14% to 25%.
The clearest day of the month is October 1, with clear, mostly clear, or partly cloudy conditions 86% of the time.
For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 44%, while on September 10, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%.
Cloud Cover Categories in October
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Spring Valley, the chance of a wet day over the course of October is gradually increasing, starting the month at 4% and ending it at 7%.
For reference, the year's highest daily chance of a wet day is 21% on February 22, and its lowest chance is 0% on June 27.
Probability of Precipitation in October
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 October in Spring Valley is gradually increasing, starting the month at 0.3 inches, when it rarely exceeds 1.0 inches, and ending the month at 0.6 inches, when it rarely exceeds 1.7 inches.
Average Monthly Rainfall in October
Over the course of October in Spring Valley, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 57 minutes, implying an average daily decrease of 1 minute, 55 seconds, and weekly decrease of 13 minutes, 23 seconds.
The shortest day of the month is October 31, with 10 hours, 53 minutes of daylight and the longest day is October 1, with 11 hours, 50 minutes of daylight.
Hours of Daylight and Twilight in October
The earliest sunrise of the month in Spring Valley is 6:42 AM on October 1 and the latest sunrise is 23 minutes later at 7:04 AM on October 31.
The latest sunset is 6:32 PM on October 1 and the earliest sunset is 35 minutes earlier at 5:57 PM on October 31.
Daylight saving time is observed in Spring Valley during 2018, but it neither starts nor ends during October, 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, 19 minutes later, at 7:59 PM, while on December 21, the shortest day of the year, it rises at 6:46 AM and sets 9 hours, 60 minutes later, at 4:46 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in October
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 Spring Valley is gradually decreasing during October, falling from 3% to 0% over the course of the month.
For reference, on August 24, the muggiest day of the year, there are muggy conditions 8% of the time, while on December 4, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in October
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 Spring Valley is essentially constant during October, remaining within 0.2 miles per hour of 6.2 miles per hour throughout.
For reference, on December 30, the windiest day of the year, the daily average wind speed is 8.2 miles per hour, while on September 9, the calmest day of the year, the daily average wind speed is 5.8 miles per hour.
Average Wind Speed in October
Wind Direction in October
Spring Valley 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 is gradually decreasing during October, falling by 3°F, from 68°F to 65°F, over the course of the month.
Average Water Temperature in October
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 Spring Valley 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 October
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 Spring Valley are rapidly increasing during October, increasing by 472°F, from 3,794°F to 4,266°F, over the course of the month.
Growing Degree Days in October
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 Spring Valley is decreasing during October, falling by 1.4 kWh, from 5.8 kWh to 4.4 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in October
For the purposes of this report, the geographical coordinates of Spring Valley are 32.745 deg latitude, -116.999 deg longitude, and 515 ft elevation.
The topography within 2 miles of Spring Valley contains very significant variations in elevation, with a maximum elevation change of 1,033 feet and an average elevation above sea level of 564 feet. Within 10 miles contains very significant variations in elevation (2,539 feet). Within 50 miles contains large variations in elevation (6,483 feet).
The area within 2 miles of Spring Valley is covered by artificial surfaces (97%), within 10 miles by artificial surfaces (60%) and shrubs (26%), and within 50 miles by shrubs (42%) and water (36%).
This report illustrates the typical weather in Spring Valley 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 6 weather stations near enough to contribute to our estimation of the temperature and dew point in Spring Valley.
For each station, the records are corrected for the elevation difference between that station and Spring Valley 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 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 and a given station.
The stations contributing to this reconstruction are: Gillespie Field (41%, 9 kilometers, north); Montgomery Field Airport (21%, 15 kilometers, northwest); San Diego International Airport (12%, 17 kilometers, west); Brown Field Municipal Airport (15%, 19 kilometers, south); Ream Field (9%, 23 kilometers, southwest); and Campo (1.7%, 51 kilometers, east).
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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 aiports and weather stations are provided by AskGeo.com .
Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.
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.