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Fall Weather in Riverdale Park California, United States

Daily high temperatures decrease by 32°F, from 92°F to 59°F, rarely falling below 53°F or exceeding 99°F.

Daily low temperatures decrease by 20°F, from 61°F to 42°F, rarely falling below 33°F or exceeding 67°F.

For reference, on July 17, the hottest day of the year, temperatures in Riverdale Park typically range from 64°F to 95°F, while on December 29, the coldest day of the year, they range from 39°F to 54°F.

Average High and Low Temperature in the Fall in Riverdale Park

Average High and Low Temperature in the Fall in Riverdale ParkSepOctNov30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FSummerWinterSep 192°FSep 192°F61°F61°FNov 3059°FNov 3059°F42°F42°FOct 184°FOct 184°F56°F56°FNov 172°FNov 172°F48°F48°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 fall temperatures. 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 the Fall in Riverdale Park

Average Hourly Temperature in the Fall in Riverdale ParkSepOctNov12 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 AMSummerWintervery coldvery coldcoldcoolcomfortablecomfortablewarmhot
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.

Talavera La Real, Spain (5,711 miles away) is the far-away foreign place with temperatures most similar to Riverdale Park (view comparison).

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The fall in Riverdale Park experiences very rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 10% to 47%.

The clearest day of the fall is September 1, with clear, mostly clear, or partly cloudy conditions 90% of the time.

For reference, on February 6, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 53%, while on July 28, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.

Cloud Cover Categories in the Fall in Riverdale Park

Cloud Cover Categories in the Fall in Riverdale ParkSepOctNov0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SummerWinterSep 190%Sep 190%Nov 3053%Nov 3053%Oct 182%Oct 182%Nov 165%Nov 165%clearmostly clearpartly cloudyovercastmostly cloudy
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 Riverdale Park, the chance of a wet day over the course of the fall is very rapidly increasing, starting the season at 1% and ending it at 22%.

For reference, the year's highest daily chance of a wet day is 29% on February 20, and its lowest chance is 0% on July 31.

Probability of Precipitation in the Fall in Riverdale Park

Probability of Precipitation in the Fall in Riverdale ParkSepOctNov0%0%5%5%10%10%15%15%20%20%25%25%SummerWinterSep 11%Sep 11%Nov 3022%Nov 3022%Oct 14%Oct 14%Nov 114%Nov 114%rain
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 season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during the fall in Riverdale Park is very rapidly increasing, starting the season at 0.1 inches, when it rarely exceeds 0.2 inches or falls below -0.0 inches, and ending the season at 2.4 inches, when it rarely exceeds 4.9 inches or falls below 0.3 inches.

Average Monthly Rainfall in the Fall in Riverdale Park

Average Monthly Rainfall in the Fall in Riverdale ParkSepOctNov0 in0 in1 in1 in2 in2 in3 in3 in4 in4 in5 in5 in6 in6 inSummerWinterSep 10.1 inSep 10.1 inNov 302.4 inNov 302.4 inOct 10.4 inOct 10.4 inNov 11.4 inNov 11.4 in
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 the fall in Riverdale Park, the length of the day is very rapidly decreasing. From the start to the end of the season, the length of the day decreases by 3 hours, 11 minutes, implying an average daily decrease of 2 minutes, 8 seconds, and weekly decrease of 14 minutes, 53 seconds.

The shortest day of the fall is November 30, with 9 hours, 46 minutes of daylight and the longest day is September 1, with 12 hours, 57 minutes of daylight.

Hours of Daylight and Twilight in the Fall in Riverdale Park

Hours of Daylight and Twilight in the Fall in Riverdale ParkSepOctNov0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrSummerWinterSep 2212 hr, 10 minSep 2212 hr, 10 minnightnightdaydayNov 309 hr, 46 minNov 309 hr, 46 minNov 110 hr, 35 minNov 110 hr, 35 min
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 latest sunrise of the fall in Riverdale Park is 7:31 AM on November 2 and the earliest sunrise is 59 minutes earlier at 6:32 AM on November 3.

The latest sunset is 7:32 PM on September 1 and the earliest sunset is 2 hours, 46 minutes earlier at 4:46 PM on November 30.

Daylight saving time (DST) starts at 1:00 AM on November 3, 2024, shifting sunrise and sunset to be an hour later.

For reference, on June 20, the longest day of the year, the Sun rises at 5:43 AM and sets 14 hours, 46 minutes later, at 8:28 PM, while on December 21, the shortest day of the year, it rises at 7:15 AM and sets 9 hours, 34 minutes later, at 4:49 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in the Fall in Riverdale Park

Sunrise & Sunset with Twilight and Daylight Saving Time in the Fall in Riverdale ParkSepOctNov12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMSummerWinter6:32 AM6:32 AMNov 35:02 PMNov 35:02 PM6:35 AM6:35 AMSep 17:32 PMSep 17:32 PM7:00 AM7:00 AMNov 304:46 PMNov 304:46 PM7:00 AM7:00 AMOct 16:46 PMOct 16:46 PMDSTNov 3DSTNov 3SolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day in the fall. 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 transitions to and from daylight saving time are indicated by the 'DST' labels.

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 the Fall in Riverdale Park

Solar Elevation and Azimuth in the Fall in Riverdale ParkSepOctNov12 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 AMSummerWinter0102020304050600010203040
northeastsouthwest
Solar elevation and azimuth in the the fall of 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 the fall of 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 the Fall in Riverdale Park

Moon Rise, Set & Phases in the Fall in Riverdale ParkSepOctNov12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMSummerWinterAug 44:14 AMAug 44:14 AMAug 1911:26 AMAug 1911:26 AMSep 26:56 PMSep 26:56 PMSep 177:35 PMSep 177:35 PMOct 211:50 AMOct 211:50 AMOct 174:27 AMOct 174:27 AMNov 15:48 AMNov 15:48 AMNov 151:29 PMNov 151:29 PMNov 3010:22 PMNov 3010:22 PMDec 151:02 AMDec 151:02 AMDec 302:28 PMDec 302:28 PM8:44 PM8:44 PM7:40 PM7:40 PM6:06 AM6:06 AM7:37 PM7:37 PM7:07 PM7:07 PM7:27 AM7:27 AM6:54 AM6:54 AM6:45 PM6:45 PM5:59 PM5:59 PM7:31 AM7:31 AM7:44 AM7:44 AM6:01 PM6:01 PM4:35 PM4:35 PM6:40 AM6:40 AM4:10 PM4:10 PM3:59 PM3:59 PM7:54 AM7:54 AM7:30 AM7:30 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.

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 Riverdale Park is essentially constant during the fall, remaining around 0% throughout.

The highest chance of a muggy day during the fall is 0% on September 11.

For reference, on July 16, the muggiest day of the year, there are muggy conditions 0% 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 the Fall in Riverdale Park

Humidity Comfort Levels in the Fall in Riverdale ParkSepOctNov0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%SummerWinterSep 110%Sep 110%Nov 300%Nov 300%Oct 10%Oct 10%Nov 10%Nov 10%comfortablecomfortabledrydryhumidhumid
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 Riverdale Park is decreasing during the fall, decreasing from 7.2 miles per hour to 6.1 miles per hour over the course of the season.

For reference, on June 18, the windiest day of the year, the daily average wind speed is 8.9 miles per hour, while on January 21, the calmest day of the year, the daily average wind speed is 5.7 miles per hour.

The lowest daily average wind speed during the fall is 5.7 miles per hour on November 1.

Average Wind Speed in the Fall in Riverdale Park

Average Wind Speed in the Fall in Riverdale ParkSepOctNov0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mphSummerWinterNov 15.7 mphNov 15.7 mphSep 17.2 mphSep 17.2 mphNov 306.1 mphNov 306.1 mphOct 16.3 mphOct 16.3 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The wind direction in Riverdale Park during the fall is predominantly out of the west from September 1 to November 28 and the north from November 28 to November 30.

Wind Direction in the Fall in Riverdale Park

Wind Direction in the Fall in Riverdale ParkWNSepOctNov0%100%20%80%40%60%60%40%80%20%100%0%SummerWinterwestnorthsoutheast
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).

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).

The growing season in Riverdale Park typically lasts for 11 months (324 days), from around January 18 to around December 7, rarely starting after February 22, or ending before November 17.

The fall in Riverdale Park is more likely than not fully within the growing season, with the chance that a given day is in the growing season rapidly decreasing from 100% to 66% over the course of the season.

Time Spent in Various Temperature Bands and the Growing Season in the Fall in Riverdale Park

Time Spent in Various Temperature Bands and the Growing Season in the Fall in Riverdale Parkgrowing seasonSepOctNov0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SummerWinter100%Sep 1100%Sep 166%Nov 3066%Nov 30100%Oct 1100%Oct 199%Nov 199%Nov 1very coldcoldcoolcomfortablewarmhotswelteringfreezing
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 Riverdale Park are very rapidly increasing during the fall, increasing by 1,256°F, from 3,568°F to 4,824°F, over the course of the season.

Growing Degree Days in the Fall in Riverdale Park

Growing Degree Days in the Fall in Riverdale ParkSepOctNov3,500°F3,500°F4,000°F4,000°F4,500°F4,500°F5,000°F5,000°FSummerWinterSep 13,568°FSep 13,568°FNov 304,824°FNov 304,824°FOct 14,223°FOct 14,223°FNov 14,662°FNov 14,662°F
The average growing degree days accumulated over the course of the fall, 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 Riverdale Park is very rapidly decreasing during the fall, falling by 4.4 kWh, from 6.9 kWh to 2.5 kWh, over the course of the season.

Average Daily Incident Shortwave Solar Energy in the Fall in Riverdale Park

Average Daily Incident Shortwave Solar Energy in the Fall in Riverdale ParkSepOctNov0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhSummerWinterSep 16.9 kWhSep 16.9 kWhNov 302.5 kWhNov 302.5 kWhOct 15.3 kWhOct 15.3 kWhNov 13.6 kWhNov 13.6 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 Riverdale Park are 37.609 deg latitude, -121.052 deg longitude, and 62 ft elevation.

The topography within 2 miles of Riverdale Park is essentially flat, with a maximum elevation change of 49 feet and an average elevation above sea level of 66 feet. Within 10 miles is essentially flat (131 feet). Within 50 miles contains only modest variations in elevation (4,324 feet).

The area within 2 miles of Riverdale Park is covered by cropland (92%), within 10 miles by cropland (79%) and artificial surfaces (18%), and within 50 miles by cropland (38%) and grassland (38%).

This report illustrates the typical weather in Riverdale Park, 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 Riverdale Park.

For each station, the records are corrected for the elevation difference between that station and Riverdale Park 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 Riverdale Park is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Riverdale Park 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 Riverdale Park 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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