September Weather in Wellfleet, United States

Last updated: February 24, 2025

In September, Wellfleet experiences a delightful transition into autumn, with average temperatures hovering around 19°C (66°F), peaking at a comfortable 24°C (76°F) during the day. As evenings cool down to a minimum of 13°C (56°F), it offers a perfect opportunity to embrace the brisk air. However, this month also brings about a notable precipitation total of 110 mm (4.3 in), falling over approximately 10 days, contributing to the region's lush landscapes. With an average humidity of 75%, September in Wellfleet presents a refreshing blend of warm days and cooler nights, ideal for outdoor adventures amidst vibrant fall foliage.

September Temperature in Wellfleet

In September, Wellfleet experiences a refreshing transition from the summer heat to the cooler autumn chill. The month brings a pleasant average temperature of 19°C (66°F), with daily highs reaching up to 24°C (76°F), making it an ideal time for outdoor adventures. While nighttime can be a bit brisk with temperatures dipping to a minimum of 13°C (56°F), the balmy days invite visitors to enjoy the pristine beaches and scenic landscapes. As summer gives way to fall, the temperatures start to drop gradually, hinting at the coolness of autumn ahead, setting a perfect backdrop for the changing foliage and seasonal festivities.

September Weather in Wellfleet: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Wellfleet, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec363638445161687065584840
Data source: Temperature data for Wellfleet generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Wellfleet

In September, Wellfleet experiences a significant increase in precipitation, with an average of 110 mm (4.3 in) of rain falling over 10 days. This marks a notable rise compared to the drier summer months, particularly August, which saw just 74 mm (2.9 in) over 7 days. As autumn approaches, the steady uptick in rainfall is reflected in the shift from the summer drought-like conditions of July and August, when annual lows of 84 mm and 74 mm were recorded, respectively. The moisture-laden September sets the stage for the wetter months ahead, with October historically peaking at 161 mm (6.3 in), suggesting that the region is transitioning into a more humid climate as it prepares for the cooler, rainier days of fall.

September Precipitation Trends in Wellfleet

The chart displays monthly precipitation patterns in Wellfleet, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec95117119130106888474110161106138
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Wellfleet

As summer transitions into autumn, September humidity in Wellfleet settles at a comfortable 75%, reflecting a gradual decline from the peak levels experienced in the more humid summer months. This slight decrease continues the trend observed since May, where humidity peaked at 75%, paving the way for crisper fall air. As the year progresses, levels oscillate, with the late autumn months bringing a rise again to 80% in November, but September stands out as a pivotal point where the air begins to feel less sticky, inviting cooler breezes and the promise of fall's natural beauty. Notably, January and February maintain the highest levels at 84%, showcasing the region's overall trend towards lower humidity as temperatures drop toward the winter months.

September Average Humidity in Wellfleet

This chart illustrates the average monthly humidity levels in Wellfleet, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec84%84%82%79%75%78%76%76%76%75%80%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Wellfleet

As summer transitions to fall in Wellfleet, the UV Index in September remains notably high at 8, indicating a very high exposure category, which is consistent with the preceding months of June, July, and August. This trend highlights the importance of sun protection, as the average burn time is a brisk 15 minutes—that’s all it takes to risk skin damage. While the UV Index decreases slightly from its peak in the summer, it serves as a reminder that sun safety should remain a priority even as the days grow shorter. For more information on UV exposure in Wellfleet throughout the year, visit Wellfleet UV Index.

Maximum UV Index Levels in Wellfleet for September

The chart shows the monthly maximum UV Index (UVI) for Wellfleet in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec2458910998642
Data source: Wellfleet September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Wellfleet

As summer fades into autumn, September in Wellfleet offers a delightful balance of warmth and sunshine, with an impressive 277 hours of sunshine gracing the month. This marks a noticeable dip from the peak brightness of July and August, which together bask in over 300 hours each. However, compared to earlier months like April's 239 hours and May's 293, September still shines brightly, hinting at lingering summer days while beckoning the cooler embrace of fall. The gradual transition in daylight hours paints a picturesque backdrop for outdoor enthusiasts and nature lovers, inviting them to savor the last golden moments of summer.

Monthly Sunshine Duration in Wellfleet: September Highlighted

The September sunshine duration represents the total number of hours Wellfleet experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec136h180h252h239h293h322h339h328h277h229h201h159h
Data source: Wellfleet September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Wellfleet During September

In Wellfleet, United States, the likelihood of sunny weather in September stands at 49%, making it one of the brighter months of the year. This trend shows a notable increase from the summer months, where the chances of sun hovered around the mid-30s to low-40s. As the summer fades, September offers a refreshing shift, bridging the sunny warmth of summer and the cooler tones of autumn. With a greater likelihood of clear skies, it's an ideal time for outdoor activities and enjoying the natural beauty of Wellfleet, setting the perfect stage for early fall adventures.

Percentage of Sunny Days in September in Wellfleet

The chart illustrates the percentage of sunny days in Wellfleet throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Wellfleet experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec32%25%54%43%42%39%37%36%49%43%47%26%
Data source: Wellfleet September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Wellfleet in September

As summer fades into autumn, September in Wellfleet offers a gentle transition with approximately 12 hours of daylight. This month marks a noticeable shift from the longer days of June and July, where residents enjoyed up to 15 hours of sunshine. Following the vibrant summer, daylight begins to wane, with September still holding onto the brightness of late summer before the days shorten further into fall. The gradual decline in daylight from the peak of 15 hours in June to 12 hours in September highlights the cyclical nature of the seasons, inviting the community to savor the last warm days of the year before autumn takes hold.

Average Daylight Hours in Wellfleet for September

The chart illustrates the variation in daylight duration in Wellfleet throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 30m10h 35m11h 58m13h 22m14h 34m15h 10m14h 50m13h 46m12h 25m11h 1m9h 47m9h 9m
Data source: Wellfleet daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Wellfleet

In Wellfleet, United States, September marks a shift in the wind patterns as the summer breezes begin to fade. Averaging 6.4 m/s (14 mph), the winds pick up slightly from their low in August, reflecting a gradual return to more robust autumnal gusts. This uptick signifies a transition to the upcoming cooler months, as October further elevates the average to 7.2 m/s (16 mph). Overall, the trend reveals that while the summer months bring gentler breezes, September heralds a refreshing increase, setting the stage for the more invigorating winds that characterize the fall season.

Average September Wind Speed in Wellfleet

The chart displays monthly wind speed patterns in Wellfleet, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec8.28.38.17.16.46.75.55.16.4 m/s7.27.77.8
Data source: Wellfleet September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Wellfleet Compares to Other Months

The weather in Wellfleet changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Wellfleet and find detailed weather information for every month.

In September, Wellfleet experiences mild temperatures with a minimum of 13°C (56°F) and an average of 19°C (66°F), peaking at 24°C (76°F). The month sees around 110 mm (4.3 in) of precipitation spread over approximately 10 days, while the humidity averages 75%. In contrast, January presents a much colder climate, with temperatures plummeting to a minimum of -12°C (11°F) and an average of just 2°C (37°F), reaching a maximum of 12°C (54°F). Although January has slightly lower precipitation at 95 mm (3.7 in) over about 11 days, the humidity rises to 84%, contributing to the chill of winter. For more detailed information on January conditions, visit Wellfleet weather in January.

When comparing the weather in September and February, there are stark contrasts in temperature and conditions. September sees a mild climate with average temperatures around 19°C (66°F) and maximums reaching 24°C (76°F), while February experiences much colder temperatures, averaging just 2°C (37°F) and peaking at only 12°C (53°F). Precipitation is quite similar between the two months, with September receiving 110 mm (4.3 in) over approximately 10 days, and February slightly higher at 117 mm (4.6 in) over 12 days. Humidity levels are also notably different; September has a humidity of 75%, whereas February is more humid at 84%. For a detailed look at February weather in Wellfleet, check out Wellfleet weather in February.

In comparing the weather patterns of September and March, there's a stark contrast in temperatures and overall climate conditions. September typically enjoys milder temperatures, ranging from a minimum of 13°C (56°F) to a maximum of 24°C (76°F), with an average of 19°C (66°F). In this month, the region experiences about 110 mm (4.3 in) of precipitation over 10 days and a humidity level of 75%. In contrast, March is much colder, with temperatures dipping to a minimum of -8°C (17°F) and only reaching a maximum of 12°C (54°F), averaging around 3°C (38°F). Precipitation in March is slightly higher at 119 mm (4.7 in) over 11 days, coupled with a higher humidity of 82%. For more detailed insights, you can check Wellfleet weather in March.

In comparing the weather between September and April, September typically offers warmer temperatures, with an average of 19°C (66°F) compared to April's cooler average of 7°C (44°F). While September enjoys a max temperature of 24°C (76°F), April reaches only up to 14°C (58°F). Precipitation levels are fairly similar, with September receiving 110 mm (4.3 in) over 10 days and April slightly wetter at 130 mm (5.1 in) over 12 days. Humidity levels are also comparable, with September at 75% and April at 79%. For a more detailed look at April weather, visit Wellfleet weather in April.

When comparing the weather in September and May, notable differences emerge. September experiences milder temperatures, with averages ranging from a minimum of 13°C (56°F) to a maximum of 24°C (76°F), while May is cooler, with average temperatures from a low of 4°C (40°F) to a high of 18°C (65°F). Both months have similar precipitation levels, with September receiving 110 mm (4.3 in) over 10 days and May slightly less at 106 mm (4.2 in) over 11 days. Interestingly, humidity remains consistent in both months at 75%, creating a comparable feel in terms of moisture, despite the differences in temperature. For more detailed insights, you can explore Wellfleet weather in May.

In comparing the weather of September and June, September tends to be slightly warmer, with average temperatures reaching 19°C (66°F) compared to June’s average of 16°C (61°F). Both months experience similar levels of precipitation, with September recording 110 mm (4.3 in) and June slightly lower at 88 mm (3.5 in), although each month sees rain on about 10 days. Humidity levels are fairly close as well, with September at 75% and June slightly higher at 78%. For more specific insights on June weather, you can refer to Wellfleet weather in June.

In comparing the weather of September and July, September tends to be slightly cooler, with average temperatures ranging from a minimum of 13°C (56°F) to a maximum of 24°C (76°F), while July enjoys warmer conditions with temperatures ranging from 16°C (60°F) to 26°C (79°F). Additionally, September experiences more precipitation, averaging 110 mm (4.3 in) over 10 days compared to July's 84 mm (3.3 in) over 8 days. Both months maintain similar humidity levels, with September at 75% and July at 76%, making the air feel consistently moist. For more details about July's specific weather patterns, check out Wellfleet weather in July.

In comparing the weather of September and August, September tends to be cooler and wetter. While August boasts a warm average temperature of 21°C (70°F) with a maximum of 26°C (79°F), September sees a decrease in the average to 19°C (66°F) and a maximum of 24°C (76°F). Additionally, September experiences more precipitation, totaling 110 mm (4.3 in) over about 10 days, in contrast to August's 74 mm (2.9 in) spread over 7 days. The humidity remains relatively stable, with both months hovering around 75-76%. For more detailed information, you can check Wellfleet weather in August.

In comparing the weather of September and October, we observe a notable decrease in average temperatures. September features a minimum of 13°C (56°F) and an average of 19°C (66°F), with a maximum of 24°C (76°F). In contrast, October's temperatures drop significantly, with a minimum of 4°C (40°F), an average of 15°C (58°F), and a maximum reaching 21°C (70°F).

Moreover, October experiences an increase in precipitation, totaling 161 mm (6.3 in) over 11 days, compared to September's 110 mm (4.3 in) over 10 days. Both months share a consistent humidity level of 75%, contributing to the cooler, damp feel of autumn. For a more detailed understanding of what to expect, you can refer to Wellfleet weather in October.

In September, the weather is generally milder, with average temperatures ranging from a minimum of 13°C (56°F) to a maximum of 24°C (76°F), while November experiences much cooler temperatures, with averages dropping to a minimum of -7°C (20°F) and a maximum of 18°C (65°F). Although both months see a similar amount of precipitation—around 110 mm (4.3 in) for September and 105 mm (4.2 in) for November—September typically has slightly less humidity at 75%, compared to November’s 80%. This shift in temperatures and humidity can significantly affect outdoor activities and the overall atmosphere of the months. For more details on weather conditions in November, you can check Wellfleet weather in November.

In September, temperatures are generally mild, ranging from a minimum of 13°C (56°F) to a maximum of 24°C (76°F), with an average of 19°C (66°F). The weather is accompanied by moderate precipitation, totaling 110 mm (4.3 inches) over approximately 10 days and maintaining a humidity level of 75%. In contrast, December brings a significant drop in temperature, with a minimum of -10°C (15°F), an average of 5°C (41°F), and a maximum of only 15°C (60°F). The month sees slightly higher precipitation, reaching 138 mm (5.4 inches) over 13 days, and experiences increased humidity at 80%. For more detailed insights on December conditions, you can visit Wellfleet weather in December.

Compare Wellfleet's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Wellfleet

As summer fades, September in Wellfleet ushers in a refreshing transition marked by milder temperatures and increased humidity. This month offers a delightful balance, with average highs gently cooling down from the summer peak, while crisp mornings hint at the approach of fall. However, the increased precipitation—with about ten days of rain—adds a touch of unpredictability, making the lush landscapes even more vibrant. Overall, September's weather greatly contrasts with the more stable warmth of summer, inviting locals and visitors alike to savor the beauty of this changing season. For further insights into the climate, check out Wellfleet Climate.