September Weather in Plymouth, United States

Last updated: February 24, 2025

September in Plymouth, United States, offers a delightful blend of warm temperatures and moderate humidity, making it a transitional month into fall. With maximum temperatures reaching 31°C (89°F) and an average of 19°C (66°F), residents and visitors can enjoy the lingering warmth of summer while experiencing cooler evenings. However, it's a month marked by 111 mm (4.4 in) of precipitation spread across 9 days, contributing to the lush landscapes. The 75% humidity can add a slight bite to the warmth, making it essential to stay hydrated. Whether you're exploring the outdoors or savoring local flavors, Plymouth in September provides a picturesque setting for memorable experiences.

September Temperature in Plymouth

As September unfolds in Plymouth, United States, the transition from summer warmth to the crispness of fall becomes evident. With temperatures beginning to cool, the month typically experiences a minimum of 10°C (50°F) and peaks at a comfortable 31°C (89°F), averaging around 19°C (66°F). This moderate climate offers a delightful balance, allowing residents and visitors to enjoy outdoor activities before the chill of autumn sets in. Notably, September maintains the warmth from the previous months, yet hints at the approaching seasonal changes with cooler nights. As the leaves begin to change and harvests abound, the September temperatures create a perfect backdrop for appreciating the onset of fall's vibrant palette.

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

The chart illustrates September temperature patterns in Plymouth, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec333538475666727266574637
Data source: Temperature data for Plymouth 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 Plymouth

In September, Plymouth experiences a notable transition in weather, with precipitation reaching 111 mm (4.4 inches) over 9 days. This amount is consistent with the region's typical late-summer rain patterns, sitting slightly above the lighter rainfall of August, which recorded just 75 mm (3.0 inches). As summer wanes, the precipitation begins to ramp up as the area anticipates the wetter months ahead. The trend is evident as September's rainfall paves the way for October's much heavier totals, further emphasizing the shift in seasonal weather dynamics. Overall, the early autumn rain serves to replenish the local environment, preparing it for the more intense rainfall that the fall typically brings.

September Precipitation Trends in Plymouth

The chart displays monthly precipitation patterns in Plymouth, 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.
JanFebMarAprMayJunJulAugSepOctNovDec891091141371059611075111168104128
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Plymouth

In Plymouth, United States, September marks the transition to autumn with a humidity level of 75%, mirroring the comfortable levels seen in October. As summer fades, humidity gradually decreases from its peak in January and February at a consistent 84%. Spring brings a slight drop, stabilizing around 79% in April before dipping further throughout the summer months—76% in both July and August. This general decline from mid-year humidity levels reflects the gradual shift in atmospheric conditions as the region moves toward cooler, drier fall weather. As a result, September offers a welcome reprieve from the muggy heat of summer, setting a pleasant tone for the season ahead.

September Average Humidity in Plymouth

This chart illustrates the average monthly humidity levels in Plymouth, 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 Plymouth

As September arrives in Plymouth, the UV Index shows a notable shift, peaking at 7, which categorizes it as high exposure, with a burn time of 25 minutes. This marks a decline from the summer months, where the index consistently reached a peak of 9, indicating very high exposure for those enjoying the outdoors. As the seasons transition, it's essential to remain vigilant about sun protection, especially as the UV Index begins to ebb but still poses a significant risk. Remember, September's weather might beckon you outside, but be mindful of the sun’s rays. For more details, check out the full information at Plymouth UV Index.

Maximum UV Index Levels in Plymouth for September

The chart shows the monthly maximum UV Index (UVI) for Plymouth 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.
JanFebMarAprMayJunJulAugSepOctNovDec356899997642
Data source: Plymouth 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 Plymouth

As summer gracefully transitions into autumn, September in Plymouth shines with an impressive 276 hours of sunlight, marking a delightful dip from the peak sunlight of July and August but still providing a generous golden glow. This month serves as a beautiful bridge, showcasing the lingering warmth of summer while hinting at the cool embrace of fall. Interestingly, September’s sunshine hours reflect a consistent trend of abundant daylight, as the city enjoys an upward trajectory from January’s mere 148 hours to the warm embrace of mid-year months. The gradual tapering off in hours reminds us that as days grow shorter, the vibrant hues of autumn are just around the corner, promising a scenic transformation that is just as captivating as the sun-drenched summer days.

Monthly Sunshine Duration in Plymouth: September Highlighted

The September sunshine duration represents the total number of hours Plymouth 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.
JanFebMarAprMayJunJulAugSepOctNovDec148h188h253h241h289h324h337h323h276h224h202h173h
Data source: Plymouth September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Plymouth During September

In Plymouth, the likelihood of sunny weather in September reaches 45%, showcasing a moderate transition from the summer months. This is a noticeable uptick from the previous months, particularly August, which sees just a 30% chance of sunshine. As we move into the fall, September's sunniness positions it as one of the more promising months, trailing only March and November. Interestingly, this trend suggests that while summer tends to be cloudier, the early autumn months offer a delightful reprieve, allowing residents and visitors to enjoy more sun-drenched days before winter arrives.

Percentage of Sunny Days in September in Plymouth

The chart illustrates the percentage of sunny days in Plymouth 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 Plymouth experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec41%31%60%43%39%39%35%30%45%41%54%31%
Data source: Plymouth September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Plymouth in September

As September unfolds in Plymouth, United States, the daylight duration experiences a gentle decline, offering 12 hours of daylight—a charming transition from the vibrant summer months. This gradual reduction marks a shift from the peak of 15 hours in June and 14 hours in July, down to a more tempered light in August and then September. The trend indicates a softening, as nature prepares for the cooler embrace of fall. Following September, daylight hours continue to dwindle, reaching 11 hours in October, reminiscent of the earlier months in winter. Overall, this rhythm of daylight signifies not just the changing seasons but also the beautiful cycle of time in this New England locale.

Average Daylight Hours in Plymouth for September

The chart illustrates the variation in daylight duration in Plymouth throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 29m10h 34m11h 58m13h 23m14h 35m15h 11m14h 51m13h 47m12h 25m11h9h 46m9h 8m
Data source: Plymouth daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Plymouth

In September, Plymouth experiences a gentle resurgence in wind activity, with an average speed of 4.1 m/s (9 mph). This marks a slight increase from the summer months, where winds languished at their lowest, dipping to 3.4 m/s (8 mph) in August. As the transition to fall begins, the air becomes brisker, hinting at the seasonal changes ahead. This trend of gradually rising wind speeds leading into autumn is consistent, as seen in previous months where January and February both maintain a steady 5 m/s (11 mph). Overall, September's winds may not be the strongest of the year, but they offer a refreshing reminder of nature's rhythm as it prepares for the cooler months.

Average September Wind Speed in Plymouth

The chart displays monthly wind speed patterns in Plymouth, 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.
JanFebMarAprMayJunJulAugSepOctNovDec5.05.05.24.64.34.23.53.44.1 m/s4.64.64.6
Data source: Plymouth September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Plymouth Compares to Other Months

The weather in Plymouth 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 Plymouth and find detailed weather information for every month.

September and January present a striking contrast in weather conditions. September boasts a wide temperature range, with minimums around 10°C (50°F) and maximums reaching up to 31°C (89°F), making it a warm and often humid month with an average of 19°C (66°F). In contrast, January is characterized by much colder temperatures, with minimums dipping to -17°C (1°F) and an average of just 1°C (34°F), while the maximum reaches a milder 18°C (65°F). Both months experience approximately 9 days of precipitation, but September sees a higher total of 111 mm (4.4 in) compared to January's 89 mm (3.5 in). Additionally, January's humidity is slightly higher at 84%, compared to September's 75%. For more details on January weather, check out Plymouth weather in January.

September and February showcase strikingly different weather patterns. In September, temperatures range from a mild 10°C (50°F) to a warm 31°C (89°F), making it a pleasant month with an average temperature of 19°C (66°F). Precipitation is moderate at 111 mm (4.4 in) over about 9 days, coupled with a humidity level of 75%. In contrast, February presents a much colder scenario, with temperatures fluctuating between -15°C (5°F) and 17°C (62°F), resulting in an average of just 2°C (35°F). Though precipitation levels are similar at 109 mm (4.3 in), it occurs over more days—around 12—alongside a higher humidity level of 84%. For more detailed insights about February weather, check out Plymouth weather in February.

September and March present contrasting weather patterns. September enjoys a milder climate with average temperatures ranging from a comfortable 19°C (66°F) to a high of 31°C (89°F), while March experiences much cooler temperatures, averaging just 3°C (39°F) with nighttime lows dropping to -11°C (12°F). Both months have similar precipitation levels, with September receiving 111 mm (4.4 in) over 9 days and March slightly higher at 114 mm (4.5 in) across 10 days. Additionally, March has a higher humidity level at 82%, compared to September's 75%, which often makes the chill feel more penetrating. For more detailed insights on March weather, consider checking Plymouth weather in March.

September and April display contrasting weather patterns, highlighting the transition from summer to fall and from winter to spring, respectively. In September, temperatures can range from a mild 10°C (50°F) to a high of 31°C (89°F), with an average of 19°C (66°F), making it generally warmer than April, which has temperatures spanning from a chilly -1°C (30°F) to a maximum of 24°C (75°F) and an average of only 8°C (47°F). Both months experience significant precipitation, with September receiving 111 mm (4.4 in) over 9 days, while April sees slightly more at 137 mm (5.4 in) across 13 days. Additionally, September boasts a humidity level of 75%, slightly lower than April's 79%, adding a touch of dampness to the spring month. For a more detailed look at April weather, visit Plymouth weather in April.

September and May present distinct weather patterns, reflecting the transition from summer to autumn and from spring to summer, respectively. In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 31°C (89°F), with an average of 19°C (66°F). The month experiences about 111 mm (4.4 in) of precipitation over 9 days, along with a consistent humidity of 75%. In contrast, May features cooler temperatures, with a minimum of 3°C (37°F) and a maximum of 28°C (82°F), averaging 13°C (56°F). Precipitation is slightly lower at 105 mm (4.1 in), occurring over 12 days, but the humidity remains the same at 75%. For more detailed insights, check out Plymouth weather in May.

In comparing the weather between September and June, both months exhibit similar average temperatures, hovering around 19°C (66°F), with maximum highs reaching 31°C (87-89°F). However, September has slightly higher minimum temperatures, averaging 10°C compared to June's 9°C. Precipitation levels are also notable; September experiences a bit more rain at 111 mm over 9 days, while June has 95 mm over 10 days. Humidity levels are fairly close, with September at 75% and June at 78%, indicating that both months can feel quite moist, but June tends to be slightly more humid. For a more detailed look at June weather, you can check out Plymouth weather in June.

In comparing the weather between September and July, September tends to be a bit cooler overall, with average temperatures ranging from a minimum of 10°C (50°F) to a maximum of 31°C (89°F). In contrast, July experiences warmer temperatures, with a minimum of 14°C (58°F) and a maximum of 34°C (93°F). Both months see similar levels of precipitation, with September recording 111 mm (4.4 in) over 9 days and July at 110 mm (4.3 in) over 10 days. Humidity is also comparable, with September at 75% and July slightly higher at 76%. For a more detailed look at July's climate, you can check Plymouth weather in July.

In comparing the weather of September and August, September experiences a slight drop in average temperature, with a minimum of 10°C (50°F) and an average of 19°C (66°F), while August maintains a warmer average of 22°C (72°F) with a minimum of 12°C (54°F). Maximum temperatures in both months remain fairly similar, peaking at 31°C (89°F) in September and 32°C (90°F) in August. Additionally, September sees increased precipitation, with 111 mm (4.4 in) of rainfall over nine days, compared to August’s 75 mm (3.0 in) across ten days. Humidity levels are comparable, with September at 75% and August slightly higher at 76%. For further insights, you can check Plymouth weather in August.

September and October present a noticeable shift in weather patterns. In September, temperatures range from a mild 10°C (50°F) at night to a warm 31°C (89°F) during the day, with an average of 19°C (66°F). The month experiences 111 mm (4.4 in) of precipitation over 9 days, maintaining a humidity of 75%. In contrast, October sees cooler temperatures, with nighttime lows dropping to 1°C (34°F) and daytime highs peaking at 25°C (78°F), resulting in an average of 14°C (58°F). There's an increase in rainfall to 168 mm (6.6 in) across 11 days, while humidity remains steady at 75%. For more detailed insights, check out Plymouth weather in October.

September and November exhibit stark contrasts in weather conditions. September typically enjoys warmer temperatures, with a minimum of 10°C (50°F) and an average of 19°C (66°F), peaking at 31°C (89°F). Additionally, September experiences moderate rainfall with 111 mm (4.4 in) over 9 days and a humidity level of 75%. In contrast, November sees much cooler temperatures, ranging from a minimum of -8°C (17°F) to an average of 8°C (46°F), and a maximum of 21°C (70°F). Precipitation levels are slightly lower at 104 mm (4.1 in) across 10 days, accompanied by a higher humidity of 80%. For more details about November weather, you can visit Plymouth weather in November.

In September, the weather is notably warmer, with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 31°C (89°F) and an average of 19°C (66°F). The month sees a total precipitation of 111 mm (4.4 in) over about 9 days, and humidity levels average around 75%. In contrast, December brings much colder temperatures, with a minimum of -15°C (6°F), an average of 3°C (37°F), and a maximum of 16°C (62°F). The month experiences slightly higher precipitation at 128 mm (5.0 in) over 11 days, accompanied by a higher humidity level of 80%. For more details on December weather, visit Plymouth weather in December.

Compare Plymouth's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Plymouth

As September unfolds in Plymouth, it marks a transition from the warmer summer days to the cooler embrace of autumn. With temperatures averaging a comfortable 19°C (66°F), the month boasts warmer highs and cooler lows, offering a pleasant reprieve from the summer heat. While September sees more rain than many other months, with about 111 mm (4.4 in) spread over nine days, this moisture helps nourish the landscape, setting the stage for the vibrant fall foliage to come. Humidity levels around 75% can make the air feel a bit sticky, yet the overall climate is still more forgiving compared to the peak summertime humidity. Embrace the dynamic September weather in Plymouth, and explore more about this beautiful locale at Plymouth Climate.