September Weather in Chatham, United States

Last updated: February 24, 2025

In Chatham, United States, September offers a delightful transition into autumn, showcasing a pleasant maximum temperature of 24°C (75°F) and an average of 19°C (66°F). Nights cool down to a minimum of 13°C (56°F), inviting cozy evenings. This month sees 116 mm (4.6 in) of rainfall spread over approximately 10 days, contributing to the area's lush greenery. With a humidity level around 75%, the weather can feel a bit muggy, but the overall experience is characterized by the crispness and charm of early fall.

September Temperature in Chatham

In September, Chatham, United States, experiences a delightful transition as summer begins to wane, with temperatures reflecting a perfect balance between warmth and crispness. The minimum temperature settles around 13°C (56°F), providing a gentle start to the month, while the average climbs to a comfortable 19°C (66°F). Days can still feel quite pleasant, peaking at a maximum of 24°C (75°F), making it an ideal time for outdoor activities. As September unfolds, the shifting climate hints at the cooler months ahead, creating a refreshing backdrop for early autumn adventures. This month serves as a captivating bridge from the warm embrace of summer to the cozy embrace of fall.

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

The chart illustrates September temperature patterns in Chatham, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec363638455261697066594840
Data source: Temperature data for Chatham generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Chatham

In September, Chatham experiences a notable shift in precipitation patterns, with an average of 116 mm (4.6 in) of rainfall over 10 days. This marks a slight decline from the previous months, particularly August, which recorded 83 mm (3.3 in) over just 8 days. September’s rainfall is indicative of the transition to fall, where wetter conditions start to re-emerge after the drier summer months of July and August. Following this month, October typically sees a spike in precipitation, reaching 169 mm (6.7 in), suggesting that September serves as a bridge, reintroducing moisture and preparing the landscape for the cooler, wetter fall season ahead. Overall, the increase in precipitation days helps to maintain the lushness of the environment as it prepares for the changes in temperature and floral activity that characterize the autumn months.

September Precipitation Trends in Chatham

The chart displays monthly precipitation patterns in Chatham, 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.
JanFebMarAprMayJunJulAugSepOctNovDec95124119131121887783116169106138
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Chatham

In September, Chatham experiences a notable shift in humidity, as the levels settle at a comfortable 75%. This figure reflects a gradual decline from the more humid summer months of July and August, where levels hovered around 76%. As autumn approaches, humidity in Chatham exhibits a steady pattern of decrease from the peak levels observed in early spring, which reached 82% in March. This trend continues into October, maintaining the same 75% mark, suggesting a smooth transition into drier conditions as the year progresses. Overall, September represents a moment of equilibrium, blending the lingering warmth of summer with the refreshing coolness of fall.

September Average Humidity in Chatham

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

As September rolls into Chatham, the UV Index remains notably high at 8, marking a small decline from the summer peak of 10 seen in July and June. This shift indicates that while the sun's rays continue to be potent, there is a slight easing in intensity as the seasons change. With a burn time of just 15 minutes, it's essential for residents and visitors to remain vigilant about sun protection, as exposure remains categorized as very high. This trend of high UV levels is consistent throughout the warmer months, peaking in May and June before tapering off into the fall. For more information and to stay sun-safe, check out the full details on the Chatham UV Index.

Maximum UV Index Levels in Chatham for September

The chart shows the monthly maximum UV Index (UVI) for Chatham 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.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098642
Data source: Chatham 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 Chatham

As summer gracefully transitions into autumn, September in Chatham, United States, boasts a delightful 280 hours of sunshine. This month continues the trend of abundant sunlight seen in the peak summer months, with hours still glowing strongly compared to the year’s beginning. After a stunning July that reached 344 hours, and a close 331 hours in August, September offers a gentle decrease, allowing residents to savor the lingering warmth without the sweltering heat. As daylight wanes in October, with a drop to 238 hours, the golden rays of September serve as a beautiful farewell to summer, inviting a reflective shift into the cozy embrace of fall.

Monthly Sunshine Duration in Chatham: September Highlighted

The September sunshine duration represents the total number of hours Chatham 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.
JanFebMarAprMayJunJulAugSepOctNovDec136h179h257h243h298h325h344h331h280h238h202h159h
Data source: Chatham September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Chatham During September

In Chatham, United States, September marks a significant transition in weather patterns, boasting a 51% chance of sunny days. This is a notable increase from the summer months, where the likelihood hovers around the low to mid-30s and 38%, showcasing a refreshing shift as autumn approaches. Compared to earlier months like June and August, the sunniest month of spring, March (55%), sets the tone for September's gradual uptick in sunshine. With October trailing closely behind at 44%, it’s clear that September enjoys a late-summer glow, inviting residents and visitors alike to embrace outdoor activities before the days grow shorter. The data illustrates a promising trend of sunny weather that invites enjoyment of the beautiful early fall in Chatham.

Percentage of Sunny Days in September in Chatham

The chart illustrates the percentage of sunny days in Chatham 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 Chatham experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec34%26%56%44%41%38%38%36%51%44%50%27%
Data source: Chatham September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Chatham in September

As September unfolds in Chatham, the daylight duration begins to wane, offering 12 hours of light each day. This marks a subtle transition from the vibrant summer days of June's 15 hours and July's 14 hours, gradually easing into the shorter days of fall. Throughout the year, daylight lengthens steadily from January's mere 9 hours to a peak in June, before starting its descent. By October, Chatham will see just 11 hours of daylight, cementing the rhythmic cycle of changing seasons. The shift from the longer bright days of summer to the crisp days of autumn is a reminder of nature's predictable yet beautiful transformations.

Average Daylight Hours in Chatham for September

The chart illustrates the variation in daylight duration in Chatham throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 31m10h 36m11h 58m13h 22m14h 33m15h 9m14h 49m13h 46m12h 25m11h 1m9h 48m9h 10m
Data source: Chatham daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Chatham

In September, the winds in Chatham, United States, average a brisk 6.3 m/s (14 mph), marking a slight uptick from the gentle breezes of summer. This month showcases a transition, as the winds pick up again from the subtle lull experienced in July and August, where speeds dipped to their lowest at 5.5 m/s (12 mph) and 5.1 m/s (12 mph), respectively. The gradual increase in wind speed as autumn approaches signals a shift in the region's climate, hinting at the stronger gusts that will characterize the coming months. With average speeds climbing back to 7.1 m/s (16 mph) in October, September serves as a pivotal moment, bridging the calm of summer with the invigorating winds of fall.

Average September Wind Speed in Chatham

The chart displays monthly wind speed patterns in Chatham, 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.
JanFebMarAprMayJunJulAugSepOctNovDec7.98.07.77.16.46.75.55.16.3 m/s7.17.47.4
Data source: Chatham September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Chatham Compares to Other Months

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

September and January present starkly contrasting weather patterns. In September, temperatures range from a mild 13°C (56°F) at night to a comfortable 24°C (75°F) during the day, with an average of 19°C (66°F). While it experiences 116 mm (4.6 in) of rainfall over about 10 days, the humidity is relatively moderate at 75%. In contrast, January features a much colder climate, with temperatures plummeting to a minimum of -13°C (10°F) and reaching a maximum of only 12°C (54°F), averaging just 2°C (37°F). Although it sees slightly less precipitation at 94 mm (3.7 in) over the same number of days, the humidity rises to 84%, making the air feel even colder. For more specifics, you can check the detailed forecast here: Chatham weather in January.

September and February present stark contrasts in weather conditions. In September, temperatures range from a mild minimum of 13°C (56°F) to a comfortable average of 19°C (66°F), peaking at 24°C (75°F). The month experiences about 116 mm (4.6 in) of precipitation over approximately 10 days, with humidity levels around 75%. In contrast, February is characterized by much colder conditions, with temperatures dropping to a minimum of -11°C (12°F) and averaging only 2°C (37°F), reaching a maximum of 11°C (53°F). Although it sees slightly more precipitation at 124 mm (4.9 in) over 12 days, the humidity is notably higher at 84%. For more detailed information, see Chatham weather in February.

September and March present quite contrasting weather conditions. In September, temperatures are generally mild, ranging from a low of 13°C (56°F) to a pleasant high of 24°C (75°F), while March features much colder temperatures, with a minimum of -8°C (18°F) and a maximum of only 12°C (54°F). Both months experience similar levels of precipitation, with September receiving 116 mm (4.6 in) over approximately 10 days, while March sees slightly more at 119 mm (4.7 in) across 11 days. Additionally, humidity levels are higher in March at 82%, compared to 75% in September, contributing to a much chillier and damp atmosphere. For those interested in a more detailed overview of March weather, check out Chatham weather in March.

September and April showcase distinct weather patterns. September tends to be milder, with average temperatures ranging from a minimum of 13°C (56°F) to a maximum of 24°C (75°F), while April is notably cooler, with temperatures ranging from 1°C (33°F) to 14°C (57°F). Both months experience significant precipitation, with September receiving 116 mm (4.6 in) over about 10 days, and April totaling 131 mm (5.1 in) across approximately 14 days. Humidity levels are also relatively high, with September at 75% and April slightly higher at 79%. For more details on April weather, visit Chatham weather in April.

When comparing the weather in September and May, September generally offers warmer temperatures, with a minimum of 13°C (56°F) and an average of 19°C (66°F), compared to May's milder minimum of 5°C (41°F) and average of 11°C (52°F). Both months experience similar levels of humidity at 75%, but September is slightly drier with 116 mm (4.6 in) of precipitation over about 10 days, while May sees a bit more rain with 121 mm (4.8 in) over 12 days. For a closer look at May's climate, check out Chatham weather in May.

When comparing the weather in September to that of June, September tends to be warmer overall. The average temperature in September reaches around 19°C (66°F), with highs of 24°C (75°F), while June's average is slightly cooler at 16°C (61°F), peaking at 22°C (73°F). Additionally, September experiences more precipitation, with 116 mm (4.6 in) over 10 days compared to June's 88 mm (3.5 in) during the same number of days. Humidity levels are relatively similar, with September at 75% and June at 78%. For more information on June weather, you can check Chatham 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 (75°F), while July typically experiences milder temperatures with a minimum of 16°C (61°F) and a maximum of 26°C (79°F). Precipitation levels are higher in September, averaging 116 mm (4.6 in) over approximately 10 days, compared to July's 77 mm (3.0 in) over 8 days. Humidity levels remain relatively similar, with September at 75% and July slightly lower at 76%. For more detailed insights on the weather during the summer, you can refer to Chatham weather in July.

In comparing the weather of September and August, September tends to be slightly cooler, with average temperatures ranging from a minimum of 13°C (56°F) to a maximum of 24°C (75°F), while August boasts higher temperatures, averaging from 16°C (61°F) to 26°C (78°F). Additionally, September experiences more rainfall, totaling 116 mm (4.6 in) over about 10 days, compared to August's 83 mm (3.3 in) across 8 days. Humidity levels remain quite similar between the two months, with September at 75% and August slightly higher at 76%. For more detailed insights on August weather, you can visit Chatham weather in August.

In September, the weather tends to be milder with temperatures ranging from a minimum of 13°C (56°F) to a maximum of 24°C (75°F), accompanied by an average of 19°C (66°F). Precipitation is relatively high at 116 mm (4.6 in) over about 10 days, and humidity levels remain consistently at 75%. In contrast, October brings cooler temperatures, with a minimum of 4°C (40°F) and an average temperature dropping to 15°C (59°F), though it can still reach up to 21°C (70°F) at times. The month sees even more precipitation, totaling 169 mm (6.7 in) across 11 days, while humidity stays steady at 75%. For more specific details on October weather, check out Chatham weather in October.

In September, the weather is typically milder, with temperatures ranging from a minimum of 13°C (56°F) to a maximum of 24°C (75°F), and an average of 19°C (66°F). The month experiences moderate rainfall, totaling 116 mm (4.6 in) over about 10 days, along with a humidity level of 75%.

In contrast, November brings cooler temperatures, where the minimum drops to -6°C (21°F) and the average settles at 9°C (49°F), peaking at 18°C (65°F). Despite slightly less rainfall at 106 mm (4.2 in) over the same number of days, the humidity increases to 80%, creating a noticeably chillier atmosphere. For more detailed information on the November climate, you can visit Chatham weather in November.

September and December present strikingly different weather patterns. In September, temperatures range from a mild 13°C (56°F) at night to a pleasant maximum of 24°C (75°F), with an average of 19°C (66°F). The month sees about 116 mm (4.6 in) of precipitation spread over approximately 10 days, and humidity levels sit at a comfortable 75%. In contrast, December experiences much colder temperatures, with lows plunging to -10°C (14°F) and a daytime maximum of only 15°C (60°F), averaging around 5°C (41°F). The precipitation increases slightly to 138 mm (5.4 in) over about 12 days, and humidity rises to 80%. For a detailed look into December weather, visit Chatham weather in December.

Compare Chatham's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Chatham

As September unfolds in Chatham, the weather presents a delightful transition from the heat of summer to the cooler embrace of autumn. With average temperatures comfortably hovering around 19°C (66°F), this month offers a refreshing respite, especially compared to the sweltering summer months. Despite the occasional showers, with about 10 days of precipitation, the overall humidity remains reasonably high at 75%, lending the air a crisp, yet soft feel. This blend of mild temperatures and intermittent rain creates an inviting atmosphere perfect for outdoor explorations. To discover more about what to expect throughout the year, visit Chatham Climate.