September Weather in Cambridge, United States

Last updated: February 24, 2025

In September, Cambridge, United States, experiences a delightful transition into the autumn season, characterized by a maximum temperature of 32°C (90°F) and an average of 19°C (66°F), making it a pleasant time for outdoor activities. The month typically greets residents with around 84 mm (3.3 in) of precipitation spread over 8 days, contributing to the lush greenery of the area. With an average humidity level of 71%, the atmosphere can feel invigorating yet slightly moist. As summer wanes, September offers a perfect blend of warmth and refreshing breezes, inviting both locals and visitors to enjoy its charm.

September Temperature in Cambridge

In September, Cambridge experiences a delightful transition as summer winds down, with temperatures ranging from a minimum of 7°C (45°F) to a maximum of 32°C (90°F). The average temperature sits at 19°C (66°F), providing the ideal setting for outdoor activities and vibrant autumnal scenery. Notably, the month retains warmth reminiscent of late summer, as the maximum temperature remains comfortably high. It marks a gentle shift towards cooler weather, setting the stage for the crisp fall days ahead. This blend of mild evenings and warm afternoons invites both locals and visitors to enjoy the changing season while basking in the beauty of Cambridge.

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

The chart illustrates September temperature patterns in Cambridge, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec313337475766727266564435
Data source: Temperature data for Cambridge 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 Cambridge

September in Cambridge sees an average precipitation of 84 mm (3.3 in), marking a subtle dip compared to the heavier rains of the spring and summer months. With only 8 days of rain, it stands out as a relatively dry month, allowing for more sunshine as summer transitions into fall. This decline in precipitation heralds the onset of drier conditions ahead, as the city braces for the impending wetter months of October and November, which typically bring much higher rainfall. The overall trend suggests a seasonal shift where late summer dryness gives way to autumn’s increased moisture, showcasing the dynamic weather patterns characteristic of this region.

September Precipitation Trends in Cambridge

The chart displays monthly precipitation patterns in Cambridge, 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.
JanFebMarAprMayJunJulAugSepOctNovDec77969614191871167284146101129
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Cambridge

As September rolls in, Cambridge experiences a refreshing shift in humidity, with levels hovering around 71%. This marks a slight increase from the relatively drier summer months of July and August, which saw humidity levels dip to 67% and 66%, respectively. While September's humidity is lower than the winter highs, which peak at 86% in January, it foreshadows a gradual rise as the city transitions into the cooler months. This month serves as a bridge between the muggy warmth of summer and the crisp autumn air, highlighting how Cambridge's climate ebbs and flows throughout the year. The increased humidity can bring a touch of comfort as the nights begin to cool, creating a dynamic and inviting atmosphere in this vibrant city.

September Average Humidity in Cambridge

This chart illustrates the average monthly humidity levels in Cambridge, 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.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%82%80%72%72%67%66%71%79%84%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Cambridge

In September, Cambridge experiences a notable shift in UV exposure as the index drops to 7, categorizing it as high. This marks a decline from the peak summer months of June through August, which consistently boasted UV levels of 9 to 10. As a result, the time for unprotected skin to burn increases to 25 minutes, offering a bit more leeway than the 15-minute burn times of earlier summer. Despite the less intense sun, it remains essential to take precautions, especially during midday hours. As we transition into fall, understanding the variations in UV intensity becomes crucial for maintaining skin health. For more detailed insights, visit Cambridge UV Index.

Maximum UV Index Levels in Cambridge for September

The chart shows the monthly maximum UV Index (UVI) for Cambridge 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.
JanFebMarAprMayJunJulAugSepOctNovDec3558910997642
Data source: Cambridge 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 Cambridge

In September, Cambridge, United States enjoys a delightful 278 hours of sunshine, marking a gradual decline from the sun-soaked peak of July and August, both boasting over 330 hours. This month beautifully bridges summer and fall, retaining warmth while welcoming a hint of autumn crispness. With sunshine hours steadily rising from January’s chilly 152 hours to summer's peak, it’s evident that Cambridge transitions smoothly from the cold grasp of winter to the vibrant energy of summer. As the days grow shorter, September still offers ample sunlight, setting the perfect stage for outdoor activities and enjoying the last days of warmth before the cooler months settle in.

Monthly Sunshine Duration in Cambridge: September Highlighted

The September sunshine duration represents the total number of hours Cambridge 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.
JanFebMarAprMayJunJulAugSepOctNovDec152h188h253h240h289h327h334h327h278h221h201h178h
Data source: Cambridge September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Cambridge During September

In September, Cambridge sees a 44% chance of sunny weather, marking a return to more favorable conditions after the summer months, where sunshine dropped to around 30% in August. This uptick aligns with the trend observed in the spring months, specifically March, which boasted a robust 61% chance of sun. Interestingly, as the year progresses toward autumn, we see a gradual recovery in sunny prospects, with October slightly trailing behind September at 39%. Overall, September stands out as a notable month for sun seekers, striking a balanced blend of warmth and clear skies, reminiscent of the brighter days of early spring.

Percentage of Sunny Days in September in Cambridge

The chart illustrates the percentage of sunny days in Cambridge 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 Cambridge experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec44%34%61%41%38%40%33%30%44%39%55%33%
Data source: Cambridge September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Cambridge in September

As summer gives way to autumn in Cambridge, United States, September sees a slight decline in daylight duration, providing about 12 hours of sunlight. This marks a transition from the long, sun-drenched days of June and July, where daylight reached a peak of 15 hours, to the upcoming shorter days of fall and winter. In contrast to the lengthy daylight of spring and summer, September's daylight remains ample for outdoor activities, yet begins to hint at the earlier sunsets that will follow in October with just 10 hours of daylight. This gradual shift not only signals the changing seasons but also invites residents to savor the beautiful hues of autumn while basking in the comfortable warmth of early fall.

Average Daylight Hours in Cambridge for September

The chart illustrates the variation in daylight duration in Cambridge throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 26m10h 33m11h 57m13h 24m14h 38m15h 14m14h 54m13h 49m12h 26m10h 59m9h 44m9h 5m
Data source: Cambridge daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Cambridge

As September arrives in Cambridge, the wind begins to shift, bringing with it a refreshing change in atmosphere. The average wind speed gently increases to 3.7 m/s (8 mph), marking a subtle rise from the calm of summer where July and August recorded their lowest figures at 3.3 m/s (7 mph) and 3.2 m/s (7 mph), respectively. This transition hints at the onset of autumn, where the wind expectation climbs gradually into October, settling back at 4.2 m/s (9 mph). The overall pattern throughout the year showcases a downward trend in wind speed during the summer months, followed by a resurgence as the seasons change. Therefore, September's breeze offers a gentle reminder of the lively gusts that will characterize the months ahead, inviting both locals and visitors to relish the cool, crisp air.

Average September Wind Speed in Cambridge

The chart displays monthly wind speed patterns in Cambridge, 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.
JanFebMarAprMayJunJulAugSepOctNovDec4.54.44.94.24.03.83.33.23.7 m/s4.24.24.2
Data source: Cambridge September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Cambridge Compares to Other Months

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

The weather in September is considerably warmer, with average temperatures around 19°C (66°F) and maximums reaching 32°C (90°F), while January experiences much colder conditions, averaging 0°C (32°F) and dipping to a minimum of -20°C (-3°F). September sees more pleasant humidity levels at 71% and about 84 mm (3.3 in) of precipitation over 8 days. In contrast, January is much wetter, with slightly reduced precipitation at 77 mm (3.0 in) across 9 days and higher humidity at 86%. For more details on January weather, you can visit Cambridge weather in January.

In comparing the weather between September and February, we can see striking contrasts. September boasts milder temperatures with a minimum of 7°C (45°F) and an average of 19°C (66°F), up to a maximum of 32°C (90°F), making it feel quite warm. In contrast, February experiences much colder conditions, with a minimum of -16°C (4°F) and an average of just 1°C (33°F). While September has a lower precipitation level of 84 mm (3.3 in) over 8 days, February slightly increases this to 96 mm (3.8 in) across 11 days, accompanied by higher humidity at 84%. For more detailed information about February weather, you can check out Cambridge weather in February.

September and March present contrasting weather patterns. In September, temperatures range from a mild 7°C (45°F) at night to a warm 32°C (90°F) during the day, with an average of 19°C (66°F) and relatively high humidity at 71%. The month sees about 84 mm (3.3 inches) of rainfall over approximately 8 days. In contrast, March experiences significantly colder temperatures, with a minimum of -14°C (7°F) and a maximum that only reaches 19°C (66°F), resulting in an average temperature of just 3°C (38°F). This month also has higher precipitation at 96 mm (3.8 inches) over about 10 days, accompanied by even higher humidity levels at 82%. For more detailed insights, you can check Cambridge weather in March.

In September, the weather typically features mild temperatures, with an average of 19°C (66°F) and maximums reaching up to 32°C (90°F). However, it also sees a fair amount of rainfall, averaging 84 mm (3.3 in) over about 8 days, and a relative humidity of 71%. In contrast, April brings cooler temperatures, starting with lows around -2°C (28°F) and averaging only 8°C (47°F). Rainfall in April is more substantial, averaging 141 mm (5.6 in) across approximately 13 days, with slightly higher humidity at 80%. For a deeper look into the weather patterns during this month, check out Cambridge weather in April.

In comparing the weather between September and May, we observe distinct differences in temperature and precipitation patterns. September enjoys a wider temperature range, with a minimum of 7°C (45°F) and an average of 19°C (66°F), peaking at 32°C (90°F). In contrast, May's temperatures are generally cooler, with a minimum of 3°C (37°F), an average of 14°C (57°F), and a maximum of 30°C (87°F). While September sees slightly less precipitation at 84 mm (3.3 in) over 8 days compared to May's 91 mm (3.6 in) across 11 days, the humidity levels remain similar, with September at 71% and May at 72%. For more detailed information on May weather, you can visit Cambridge weather in May.

In comparing the weather of September and June, both months feature similar average temperatures, ranging from a minimum of 7-8°C (45-46°F) to a maximum of 32°C (90-91°F), making them comfortably warm. However, September typically enjoys slightly less precipitation, with 84 mm (3.3 in) over 8 days, compared to June's 87 mm (3.4 in) over 10 days. Humidity levels are quite comparable as well, with September at 71% and June at 72%. This means that while both months boast pleasant temperatures, June tends to be a bit wetter. For a deeper look into June's climate specifics, visit Cambridge weather in June.

When comparing the weather in September and July, we see notable differences in temperature and precipitation patterns. September experiences a wider temperature range, with minimums dropping to 7°C (45°F) and maximums reaching 32°C (90°F), resulting in an average of 19°C (66°F). In contrast, July is warmer overall, with temperatures ranging from a minimum of 14°C (57°F) to a maximum of 33°C (91°F), and an average of 22°C (73°F). Additionally, September sees less precipitation with 84 mm (3.3 in) accumulating over 8 days, compared to July's 116 mm (4.6 in) over 11 days. Humidity levels are slightly higher in September at 71%, while July maintains a level of 67%. For more detailed insights, you can check Cambridge weather in July.

In comparison to August, September experiences a noticeable drop in minimum temperatures, with lows averaging 7°C (45°F) compared to August's 13°C (56°F). While both months see a maximum temperature peak at 32°C (90°F), September's average temperature is slightly cooler at 19°C (66°F), down from August's 22°C (73°F). Rainfall is more pronounced in September, with 84 mm (3.3 in) of precipitation across 8 days, unlike August's 72 mm (2.8 in) spread over 10 days. Humidity levels also rise in September to 71%, compared to August's 66%. For a more detailed look at August weather, visit Cambridge weather in August.

In September, the weather typically features a broader temperature range, with lows around 7°C (45°F) and highs reaching up to 32°C (90°F), allowing for pleasant, warm days contrasted by cooler nights. However, as October arrives, the climate takes a noticeable turn; temperatures drop significantly, with minimums dipping to 0°C (33°F) and an average of only 13°C (57°F). Additionally, October experiences increased precipitation, with 146 mm (5.8 in) falling over 11 days compared to September's 84 mm (3.3 in) over 8 days. As humidity rises slightly from 71% to 78%, the transition into fall becomes more apparent. For more detailed insights, check Cambridge weather in October.

September and November present a stark contrast in weather conditions. In September, the temperatures range from a comfortable minimum of 7°C (45°F) to a warm maximum of 32°C (90°F), offering an average of 19°C (66°F). With 84 mm (3.3 inches) of precipitation over 8 days, humidity sits at 71%. In contrast, November experiences significantly colder temperatures, with minimums dropping to -11°C (13°F) and an average of only 6°C (44°F). The maximum temperature reaches up to 22°C (71°F), but the average feels much chillier, accompanied by increased precipitation of 101 mm (4.0 inches) over 10 days and higher humidity at 84%. For more detailed insights, you can check Cambridge weather in November.

September and December present a stark contrast in weather patterns. September enjoys warmer temperatures, with an average of 19°C (66°F) and highs reaching up to 32°C (90°F), while December plunges to an average of just 2°C (35°F), with lows dropping to -18°C (0°F). Precipitation is also notable, as September experiences 84 mm (3.3 in) over 8 days, compared to December's 129 mm (5.1 in) over 10 days. Additionally, December tends to be more humid, with a humidity level of 81% compared to September's 71%. For a closer look at December weather specifics, check Cambridge weather in December.

Compare Cambridge's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Cambridge

As summer gives way to autumn, September in Cambridge showcases a delightful transition marked by warm days and cooler nights. With an average temperature of 19°C, this month offers comfortable warmth, yet it contrasts sharply with the peaks often seen in July and August. Notably, the 71% humidity adds a hint of mugginess to the air, but it’s balanced by the decreasing precipitation, totaling around 84 mm over eight days. This shift in weather sets the stage for the vibrant fall foliage, making it a picturesque time to explore the area. For more insights on how the weather shapes the local climate, visit Cambridge Climate.