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September Weather in Seaside Oregon, United States

Daily high temperatures decrease by 3°F, from 67°F to 64°F, rarely falling below 59°F or exceeding 76°F.

Daily low temperatures decrease by 4°F, from 54°F to 50°F, rarely falling below 42°F or exceeding 59°F.

For reference, on August 17, the hottest day of the year, temperatures in Seaside typically range from 55°F to 68°F, while on December 22, the coldest day of the year, they range from 39°F to 48°F.

Average High and Low Temperature in September in Seaside

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 Seaside

Average Hourly Temperature in September in SeasideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 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 AMAugOctcoldcoldcoolcomfortable
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.

Plougourvest, France (4,975 miles away) is the far-away foreign place with temperatures most similar to Seaside (view comparison).

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The month of September in Seaside experiences rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 33% to 45%.

The clearest day of the month is September 1, with clear, mostly clear, or partly cloudy conditions 67% of the time.

For reference, on January 9, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 74%, while on August 2, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 77%.

Cloud Cover Categories in September in Seaside

Cloud Cover Categories in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%AugOctSep 167%Sep 167%Sep 3055%Sep 3055%Sep 1166%Sep 1166%Sep 2162%Sep 2162%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 Seaside, the chance of a wet day over the course of September is very rapidly increasing, starting the month at 16% and ending it at 28%.

For reference, the year's highest daily chance of a wet day is 62% on November 17, and its lowest chance is 6% on August 3.

Probability of Precipitation in September in Seaside

Probability of Precipitation in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%0%5%5%10%10%15%15%20%20%25%25%30%30%35%35%40%40%45%45%50%50%55%55%AugOctSep 116%Sep 116%Sep 3028%Sep 3028%Sep 1120%Sep 1120%Sep 2123%Sep 2123%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 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 Seaside is very rapidly increasing, starting the month at 1.4 inches, when it rarely exceeds 2.8 inches or falls below 0.1 inches, and ending the month at 3.6 inches, when it rarely exceeds 6.9 inches or falls below 0.7 inches.

Average Monthly Rainfall in September in Seaside

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 Seaside, 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, 33 minutes, implying an average daily decrease of 3 minutes, 12 seconds, and weekly decrease of 22 minutes, 24 seconds.

The shortest day of the month is September 30, with 11 hours, 43 minutes of daylight and the longest day is September 1, with 13 hours, 15 minutes of daylight.

Hours of Daylight and Twilight in September in Seaside

Hours of Daylight and Twilight in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrAugOctSep 2212 hr, 12 minSep 2212 hr, 12 minnightnightdaydaySep 113 hr, 15 minSep 113 hr, 15 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 earliest sunrise of the month in Seaside is 6:37 AM on September 1 and the latest sunrise is 36 minutes later at 7:13 AM on September 30.

The latest sunset is 7:52 PM on September 1 and the earliest sunset is 56 minutes earlier at 6:56 PM on September 30.

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

For reference, on June 20, the longest day of the year, the Sun rises at 5:24 AM and sets 15 hours, 45 minutes later, at 9:10 PM, while on December 21, the shortest day of the year, it rises at 7:54 AM and sets 8 hours, 38 minutes later, at 4:33 PM.

Sunrise & Sunset with Twilight in September in Seaside

Sunrise & Sunset with Twilight in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930302 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMAugOct6:37 AM6:37 AMSep 17:52 PMSep 17:52 PM7:13 AM7:13 AMSep 306:56 PMSep 306:56 PM6:49 AM6:49 AMSep 117:33 PMSep 117:33 PMSolarMidnightSolarMidnightSolarNoonSunriseSunset
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 Seaside

Solar Elevation and Azimuth in September in SeasideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 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 AMAugOct001010202020303040405000010102020303030405060
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 Seaside

Moon Rise, Set & Phases in September in SeasideSep11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 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 AM5:57 AM5:57 AM9:16 PM9:16 PM8:14 PM8:14 PM5:58 AM5:58 AM6:04 AM6:04 AM7:59 PM7:59 PM7:22 PM7:22 PM7:40 AM7:40 AM7:10 AM7:10 AM6:50 PM6:50 PM6:02 PM6:02 PM7:57 AM7:57 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%4:56 AMENE7:42 PMWNW-12:24 PMS249,340 mi
2
0%6:04 AMENE7:59 PMWNW-1:05 PMS250,699 mi
3
1%7:10 AME8:14 PMW-1:45 PMS251,694 mi
4
3%8:14 AME8:28 PMW-2:23 PMS252,277 mi
5
7%9:18 AME8:43 PMW-3:02 PMS252,384 mi
6
13%10:23 AMESE8:59 PMWSW-3:41 PMS251,939 mi
7
20%11:29 AMESE9:17 PMWSW-4:23 PMS250,868 mi
8
29%12:37 PMESE9:40 PMWSW-5:08 PMS249,119 mi
9
38%1:46 PMSE10:09 PMSW-5:58 PMS246,673 mi
10
50%2:54 PMSE10:48 PMSW-6:51 PMS243,571 mi
11
59%3:58 PMSE11:40 PMSW-7:49 PMS239,928 mi
12
70%4:53 PMSE--8:49 PMS235,943 mi
13
80%-12:45 AMSW5:37 PMSE9:49 PMS231,902 mi
14
88%-2:02 AMSW6:11 PMESE10:48 PMS228,152 mi
15
95%-3:25 AMWSW6:39 PMESE11:44 PMS225,057 mi
16
97%-4:50 AMWSW7:01 PMESE--
17
100%-6:15 AMW7:22 PME12:37 AMS222,941 mi
18
100%-7:40 AMW7:41 PME1:28 AMS222,033 mi
19
98%-9:05 AMWNW8:02 PMENE2:19 AMS222,421 mi
20
92%-10:31 AMWNW8:26 PMENE3:11 AMS224,034 mi
21
84%-11:56 AMWNW8:55 PMNE4:04 AMS226,664 mi
22
74%-1:18 PMNW9:32 PMNE5:01 AMS230,008 mi
23
63%-2:33 PMNW10:20 PMNE5:59 AMS233,724 mi
24
50%-3:35 PMNW11:19 PMNE6:57 AMS237,492 mi
25
41%-4:24 PMNW-7:54 AMS241,049 mi
26
31%12:26 AMNE5:00 PMNW-8:48 AMS244,214 mi
27
22%1:36 AMNE5:27 PMWNW-9:37 AMS246,885 mi
28
14%2:47 AMENE5:49 PMWNW-10:23 AMS249,022 mi
29
8%3:55 AMENE6:06 PMWNW-11:05 AMS250,632 mi
30
4%5:01 AMENE6:22 PMW-11:45 AMS251,743 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 Seaside is essentially constant during September, remaining around 0% throughout.

For reference, on July 25, 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 September in Seaside

Humidity Comfort Levels in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%AugOctSep 10%Sep 10%Sep 300%Sep 300%Sep 110%Sep 110%Sep 210%Sep 210%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 Seaside is gradually increasing during September, increasing from 6.2 miles per hour to 7.0 miles per hour over the course of the month.

For reference, on December 3, the windiest day of the year, the daily average wind speed is 10.5 miles per hour, while on August 17, the calmest day of the year, the daily average wind speed is 6.0 miles per hour.

Average Wind Speed in September in Seaside

Average Wind Speed in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mph14 mph14 mphAugOctSep 16.2 mphSep 16.2 mphSep 307.0 mphSep 307.0 mphSep 116.4 mphSep 116.4 mph
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 Seaside throughout September is predominantly from the north, with a peak proportion of 52% on September 1.

Wind Direction in September in Seaside

Wind Direction in September in SeasideNSSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%20%80%40%60%60%40%80%20%100%0%AugOctwestsouthnortheast
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).

Seaside 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 Seaside is gradually decreasing during September, falling by 2°F, from 59°F to 56°F, over the course of the month.

Average Water Temperature in September in Seaside

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).

The growing season in Seaside typically lasts for 8.9 months (272 days), from around March 4 to around December 1, rarely starting before January 26 or after March 31, and rarely ending before November 4 or after January 5.

The month of September in Seaside is reliably fully within the growing season.

Time Spent in Various Temperature Bands and the Growing Season in September in Seaside

Time Spent in Various Temperature Bands and the Growing Season in September in Seasidegrowing seasongrowing seasonSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%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 16very coldcoldcoolcomfortable
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 Seaside are increasing during September, increasing by 248°F, from 1,108°F to 1,356°F, over the course of the month.

Growing Degree Days in September in Seaside

Growing Degree Days in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930301,000°F1,000°F1,100°F1,100°F1,200°F1,200°F1,300°F1,300°F1,400°F1,400°F1,500°F1,500°F1,600°F1,600°FAugOctSep 11,108°FSep 11,108°FSep 301,356°FSep 301,356°FSep 111,203°FSep 111,203°F
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 Seaside is rapidly decreasing during September, falling by 1.7 kWh, from 5.4 kWh to 3.7 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in September in Seaside

Average Daily Incident Shortwave Solar Energy in September in SeasideSep1122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhAugOctSep 15.4 kWhSep 15.4 kWhSep 303.7 kWhSep 303.7 kWhSep 114.8 kWhSep 114.8 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 Seaside are 45.993 deg latitude, -123.923 deg longitude, and 3 ft elevation.

The topography within 2 miles of Seaside contains very significant variations in elevation, with a maximum elevation change of 883 feet and an average elevation above sea level of 97 feet. Within 10 miles contains very significant variations in elevation (2,661 feet). Within 50 miles contains large variations in elevation (3,684 feet).

The area within 2 miles of Seaside is covered by water (35%), herbaceous vegetation (33%), and trees (28%), within 10 miles by water (42%) and trees (39%), and within 50 miles by water (49%) and trees (33%).

This report illustrates the typical weather in Seaside, 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 Seaside.

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

Please review our full terms contained on our Terms of Service page.