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September Weather in Oceanside California, United States

Daily high temperatures are around 75°F, rarely falling below 69°F or exceeding 83°F.

Daily low temperatures decrease by 4°F, from 63°F to 60°F, rarely falling below 53°F or exceeding 69°F.

For reference, on August 24, the hottest day of the year, temperatures in Oceanside typically range from 64°F to 76°F, while on December 24, the coldest day of the year, they range from 45°F to 65°F.

Average High and Low Temperature in September in Oceanside

Average High and Low Temperature in September in OceansideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303045°F45°F50°F50°F55°F55°F60°F60°F65°F65°F70°F70°F75°F75°F80°F80°F85°F85°FAugOctSep 176°FSep 176°F63°F63°FSep 3074°FSep 3074°F60°F60°FSep 1176°FSep 1176°F62°F62°FSep 2175°FSep 2175°F61°F61°FNowNow
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 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 in Oceanside

Average Hourly Temperature in September in OceansideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 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 AMAugOctNowNowcoolcoolcomfortablewarmcold
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.

Cape Town, Western Cape, South Africa (9,923 miles away) is the far-away foreign place with temperatures most similar to Oceanside (view comparison).

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The month of September in Oceanside experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 11% throughout the month. The lowest chance of overcast or mostly cloudy conditions is 9% on September 6.

The clearest day of the month is September 6, with clear, mostly clear, or partly cloudy conditions 91% of the time.

For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 42%, while on September 6, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%.

Cloud Cover Categories in September in Oceanside

Cloud Cover Categories in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%AugOctFeb 2058%Feb 2058%Sep 190%Sep 190%Sep 3087%Sep 3087%Sep 1190%Sep 1190%Sep 2188%Sep 2188%NowNowclearmostly clearovercastpartly cloudymostly 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 Oceanside, the chance of a wet day over the course of September is essentially constant, remaining around 3% throughout.

For reference, the year's highest daily chance of a wet day is 21% on February 21, and its lowest chance is 1% on June 25.

Probability of Precipitation in September in Oceanside

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 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 September in Oceanside is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 1.1 inches or falling below -0.0 inches.

Average Monthly Rainfall in September in Oceanside

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 September in Oceanside, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 59 minutes, implying an average daily decrease of 2 minutes, 1 second, and weekly decrease of 14 minutes, 8 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, 49 minutes of daylight.

Hours of Daylight and Twilight in September in Oceanside

Hours of Daylight and Twilight in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrAugOctSep 2212 hr, 9 minSep 2212 hr, 9 minnightnightdaydaySep 112 hr, 49 minSep 112 hr, 49 minNowNow
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 earliest sunrise of the month in Oceanside is 6:24 AM on September 1 and the latest sunrise is 19 minutes later at 6:43 AM on September 30.

The latest sunset is 7:13 PM on September 1 and the earliest sunset is 39 minutes earlier at 6:34 PM on September 30.

Daylight saving time is observed in Oceanside during 2024, but it neither starts nor ends during September, so the entire month is in daylight saving time.

For reference, on June 20, the longest day of the year, the Sun rises at 5:40 AM and sets 14 hours, 21 minutes later, at 8:01 PM, while on December 21, the shortest day of the year, it rises at 6:49 AM and sets 9 hours, 57 minutes later, at 4:46 PM.

Sunrise & Sunset with Twilight in September in Oceanside

Sunrise & Sunset with Twilight in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930302 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMAugOct6:24 AM6:24 AMSep 17:13 PMSep 17:13 PM6:43 AM6:43 AMSep 306:34 PMSep 306:34 PM6:30 AM6:30 AMSep 117:00 PMSep 117:00 PMSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of September. 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 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 September in Oceanside

Solar Elevation and Azimuth in September in OceansideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 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 AMAugOct00101020202030304040505060000101020203030304040505060NowNow
northeastsouthwest
Solar elevation and azimuth over the course of September 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 September 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 September in Oceanside

Moon Rise, Set & Phases in September in OceansideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMAugOctAug 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 AM6:06 AM6:06 AM8:20 PM8:20 PM7:15 PM7:15 PM5:59 AM5:59 AM5:57 AM5:57 AM7:17 PM7:17 PM6:51 PM6:51 PM7:11 AM7:11 AM6:37 AM6:37 AM6:33 PM6:33 PM5:48 PM5:48 PM7:09 AM7:09 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.
Sep 2024IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
2%4:59 AMENE6:51 PMWNW-11:58 AMS249,314 mi
2
0%5:57 AMENE7:17 PMWNW-12:40 PMS250,679 mi
3
1%6:53 AME7:41 PMW-1:19 PMS251,680 mi
4
3%7:48 AME8:05 PMW-1:58 PMS252,271 mi
5
7%8:43 AME8:28 PMW-2:36 PMS252,387 mi
6
13%9:38 AMESE8:53 PMWSW-3:16 PMS251,952 mi
7
20%10:34 AMESE9:21 PMWSW-3:58 PMS250,893 mi
8
28%11:33 AMESE9:52 PMWSW-4:42 PMS249,155 mi
9
38%12:33 PMESE10:30 PMWSW-5:31 PMS246,722 mi
10
50%1:34 PMESE11:15 PMSW-6:25 PMS243,632 mi
11
59%2:35 PMSE--7:22 PMS239,998 mi
12
69%-12:09 AMSW3:31 PMSE8:21 PMS236,018 mi
13
79%-1:12 AMWSW4:22 PMESE9:21 PMS231,977 mi
14
88%-2:21 AMWSW5:06 PMESE10:20 PMS228,219 mi
15
95%-3:33 AMWSW5:45 PMESE11:15 PMS225,108 mi
16
97%-4:46 AMWSW6:19 PMESE--
17
100%-5:59 AMW6:51 PME12:08 AMS222,971 mi
18
100%-7:11 AMW7:22 PME12:59 AMS222,038 mi
19
98%-8:23 AMW7:54 PMENE1:50 AMS222,401 mi
20
92%-9:37 AMWNW8:29 PMENE2:42 AMS223,992 mi
21
84%-10:50 AMWNW9:09 PMENE3:36 AMS226,606 mi
22
75%-12:02 PMWNW9:56 PMENE4:32 AMS229,941 mi
23
64%-1:11 PMNW10:49 PMNE5:31 AMS233,654 mi
24
50%-2:12 PMNW11:47 PMNE6:30 AMS237,425 mi
25
41%-3:04 PMWNW-7:28 AMS240,988 mi
26
31%12:49 AMENE3:48 PMWNW-8:22 AMS244,162 mi
27
22%1:52 AMENE4:24 PMWNW-9:11 AMS246,843 mi
28
14%2:53 AMENE4:55 PMWNW-9:57 AMS248,990 mi
29
8%3:51 AMENE5:22 PMWNW-10:39 AMS250,609 mi
30
4%4:48 AME5:46 PMW-11:19 AMS251,728 mi

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 Oceanside is rapidly decreasing during September, falling from 22% to 9% over the course of the month.

For reference, on August 21, the muggiest day of the year, there are muggy conditions 24% of the time, while on January 9, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in September in Oceanside

Humidity Comfort Levels in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%AugOctSep 122%Sep 122%Sep 309%Sep 309%Sep 1120%Sep 1120%Sep 2114%Sep 2114%NowNowmuggymuggyhumidhumidcomfortablecomfortabledrydryoppressiveoppressive
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 Oceanside is essentially constant during September, remaining within 0.1 miles per hour of 5.4 miles per hour throughout.

For reference, on February 19, the windiest day of the year, the daily average wind speed is 7.2 miles per hour, while on August 14, the calmest day of the year, the daily average wind speed is 5.3 miles per hour.

Average Wind Speed in September in Oceanside

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The hourly average wind direction in Oceanside throughout September is predominantly from the west, with a peak proportion of 65% on September 1.

Wind Direction in September in Oceanside

Wind Direction in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%20%80%40%60%60%40%80%20%100%0%AugOctNowNowwestnorthsoutheast
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).

Oceanside 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 Oceanside is essentially constant during September, remaining within 1°F of 69°F throughout.

Average Water Temperature in September in Oceanside

Average Water Temperature in September in OceansideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303062°F62°F64°F64°F66°F66°F68°F68°F70°F70°F72°F72°F74°F74°FAugOctSep 170°FSep 170°FSep 3068°FSep 3068°FSep 1169°FSep 1169°FSep 2169°FSep 2169°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

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 Oceanside 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 September in Oceanside

Time Spent in Various Temperature Bands and the Growing Season in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%AugOct100%Sep 16100%Sep 16NowNowcoldcoolcomfortablewarm
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 Oceanside are rapidly increasing during September, increasing by 526°F, from 2,947°F to 3,472°F, over the course of the month.

Growing Degree Days in September in Oceanside

Growing Degree Days in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930302,600°F2,600°F2,800°F2,800°F3,000°F3,000°F3,200°F3,200°F3,400°F3,400°F3,600°F3,600°F3,800°F3,800°FAugOctSep 12,947°FSep 12,947°FSep 303,472°FSep 303,472°FSep 113,137°FSep 113,137°FNowNow
The average growing degree days accumulated over the course of September, 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 Oceanside is decreasing during September, falling by 1.2 kWh, from 6.9 kWh to 5.7 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in September in Oceanside

Average Daily Incident Shortwave Solar Energy in September in OceansideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhAugOctSep 16.9 kWhSep 16.9 kWhSep 305.7 kWhSep 305.7 kWhSep 116.5 kWhSep 116.5 kWhNowNow
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 Oceanside are 33.196 deg latitude, -117.379 deg longitude, and 66 ft elevation.

The topography within 2 miles of Oceanside contains only modest variations in elevation, with a maximum elevation change of 240 feet and an average elevation above sea level of 54 feet. Within 10 miles contains only modest variations in elevation (1,060 feet). Within 50 miles contains very significant variations in elevation (6,736 feet).

The area within 2 miles of Oceanside is covered by artificial surfaces (66%) and water (33%), within 10 miles by water (46%) and artificial surfaces (29%), and within 50 miles by water (43%) and shrubs (33%).

This report illustrates the typical weather in Oceanside, 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 Oceanside.

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