Last updated: February 24, 2025
In September, Greenwich, United States experiences a charming transition in weather, with maximum temperatures reaching 33°C (91°F) and an inviting average of 20°C (69°F). A refreshing minimum temperature of 8°C (47°F) marks the cooler evenings, making the month perfect for outdoor activities. Though 98 mm (3.8 in) of rainfall is recorded over 9 days, the moderate humidity of 68% adds to the overall pleasantness of the climate. Embrace the beauty of September in Greenwich, where summer warmth lingers while early autumn breezes begin to unfold.
In September, Greenwich experiences a delightful shift towards warmer days as summer makes its graceful exit. The minimum temperature settles at a comfortable 8°C (47°F), while the average climbs to a pleasant 20°C (69°F), peaking at a maximum of 33°C (91°F). This month serves as a transitional bridge, showcasing the gradual cooling that follows the heat of summer. The drop in early morning temperatures invites crispness, contrasting beautifully with the lingering warmth of afternoons, making it an ideal time for outdoor activities and enjoying the vibrant fall scenery. As leaves begin to hint at their autumn hues, September embodies a perfect balance of warmth and coolness, setting a picturesque backdrop for the changing seasons.
In September, Greenwich experiences an average precipitation of 98 mm (3.8 in), which falls over 9 days—a notable dip from the wetter summer months. This decrease signals the transition into autumn, as the rainfall tends to ease compared to the previous months, particularly July and August, which are known for their heavy downpours at 143 mm (5.6 in) and 123 mm (4.8 in) respectively. The weather during September mirrors a blend of lingering summer warmth with a hint of fall crispness, inviting locals to enjoy the vibrant changing foliage while experiencing this moderate rainfall pattern. As the season progresses into October, precipitation picks up again, hinting at the wet autumn ahead, with an average of 132 mm (5.2 in) expected.
In September, Greenwich experiences a slight reprieve from the summer's heat, with humidity levels averaging around 68%. This marks a moderate increase from the drier summer months of July and August, which recorded 62% and 65%, respectively. As the seasons transition, humidity gradually rises again, heading towards the wetter fall months, where October sees an uptick to 74%. Overall, September serves as a bridge between the warm, humid summer and the cooler, more humid autumn, highlighting a gentle shift in the climate as the region prepares for the months ahead.
In September, Greenwich, United States, experiences a UV Index of 8, placing it in the very high exposure category with a burn time of just 15 minutes. This reflects a gradual decrease from the peak of summer months, when the UV Index reached a maximum of 10 in both May and June. Overall, the trend throughout the year indicates that as summer transitions into fall, the UV levels slowly decline, yet remain challenging enough to warrant sun protection. So, while the intensity may slightly wane, it’s still crucial to be mindful of UV exposure in September. For more details, visit the Greenwich UV Index.
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As summer transitions into fall, September in Greenwich shines brightly with an impressive 278 hours of sunshine. This marks a slight decrease from the sun-drenched peak of 339 hours in July but still maintains a strong lead over the earlier months of the year. Following a pattern of increasing daylight, September continues the trend set by August's 315 hours, offering a warm farewell to summer. As the days gradually shorten into October, the fading sunlight invites residents to savor the last golden hues before autumn fully embraces the region.
In September, residents of Greenwich can expect a 44% chance of sunny weather, a figure that sits comfortably above the summer averages but slightly below the buoyant early spring month of March, which boasts a 56% likelihood of sunshine. As summer gives way to fall, September's sun potential contrasts sharply with August's 29%, indicating a gradual renewal of light after the low point of summer's latter days. While the month doesn't quite reach the sunniness of November, which surprises with a 55% chance, it does maintain a favorable outlook, suggesting that early autumn’s charm extends into the skies as well.
As summer draws to a close, September in Greenwich witnesses a gentle transition, with daylight lasting 12 hours. This marks a soft decline from the 15 hours experienced in June, reflecting nature's gradual shift towards autumn. After the long, sunlit days of May and June, the waning daylight serves as a reminder that shorter days are on the horizon, culminating in just 9 hours of sunlight by December. The rhythm of the seasons is evident as we move through the months, with each period of daylight reflecting a changing landscape and a distinct ambiance that invites contemplation and connection to the cyclical dance of the earth.
As September unfolds in Greenwich, the average wind speed begins to pick up slightly after the warm summer months, settling at 3.0 m/s (7 mph). This marks a gentle increase from the subdued breezes of July and August, where winds were at their lowest, averaging 2.5 m/s (6 mph) and 2.4 m/s (5 mph), respectively. The arrival of autumn brings refreshingly crisp air, signaling a transition that continues into the following months. Interestingly, October and November maintain a similar breeze at 3.1 m/s and 3.0 m/s, respectively, suggesting a consistent pattern that provides both relief and revitalization as the season shifts. This interplay between rising autumn winds and cooling temperatures not only enhances the beauty of the changing landscape but also invites outdoor enthusiasts to enjoy the invigorating atmosphere of Greenwich during this picturesque time of year.
The weather in Greenwich 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 Greenwich and find detailed weather information for every month.
September and January present stark contrasts in weather. September boasts pleasant temperatures, with minimums around 8°C (47°F) and maximums reaching up to 33°C (91°F), averaging 20°C (69°F). It experiences quite a bit of rainfall, with 98 mm (3.8 in) over about 9 days, alongside a humidity level of 68%. In contrast, January is characterized by much colder conditions, where temperatures can plummet to a minimum of -18°C (0°F) and typically average around 0°C (33°F), with maximums reaching 18°C (64°F). Precipitation in January is lighter at 69 mm (2.7 in) over 8 days, but humidity is higher at 84%. For a more detailed look, you can check Greenwich weather in January.
September and February present starkly contrasting weather conditions. In September, temperatures range from a mild 8°C (47°F) at night to a warm 33°C (91°F) during the day, with an average temperature of 20°C (69°F). The month experiences about 98 mm (3.8 in) of precipitation over 9 days, along with a humidity of 68%. In contrast, February can be quite harsh, with minimum temperatures plunging to -16°C (3°F) and an average of only 2°C (35°F). The daytime highs reach a milder 20°C (68°F), but the month sees slightly more precipitation at 101 mm (4.0 in), spread over 11 days, and a higher humidity of 82%. For detailed information, you can check Greenwich weather in February.
In comparing the weather of September and March, notable contrasts emerge. September typically enjoys milder temperatures, ranging from a minimum of 8°C (47°F) to a maximum of 33°C (91°F), resulting in an average of 20°C (69°F). Conversely, March can experience chillier conditions, with temperatures dipping as low as -10°C (15°F) and averaging only 5°C (41°F), although it can peak at 24°C (76°F). Precipitation levels are fairly similar, with September receiving about 98 mm (3.8 in) over 9 days compared to March's 93 mm (3.7 in) over 10 days. Additionally, March tends to be slightly more humid at 81%, compared to September's 68%. For further details, you can check Greenwich weather in March.
September and April showcase contrasting weather conditions, reflecting the transition from summer to autumn and winter to spring, respectively. In September, temperatures range more widely, with a minimum of 8°C (47°F), an average of 20°C (69°F), and a maximum reaching up to 33°C (91°F). The month typically experiences 98 mm (3.8 in) of precipitation over about 9 days, coupled with a humidity level of 68%.
In contrast, April presents cooler temperatures, with a minimum of -2°C (30°F) and an average of 10°C (51°F), peaking at 27°C (81°F). This month has slightly higher precipitation, accumulating 114 mm (4.5 in) over approximately 12 days, while humidity rises to 78%. For more specific insights into April weather patterns, you can visit Greenwich weather in April.
September and May exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 8°C (47°F) to a maximum of 33°C (91°F), with an average temperature of 20°C (69°F). The month experiences moderate rainfall, with 98 mm (3.8 in) of precipitation over 9 days, coupled with humidity levels around 68%. In contrast, May sees cooler temperatures, with a minimum of 2°C (36°F) and an average of 16°C (61°F), peaking at 31°C (89°F). Rainfall is slightly higher in May, totaling 114 mm (4.5 in) over 12 days, and the humidity remains comparable at 69%. For more details on May weather, you can visit Greenwich weather in May.
When comparing the weather of September and June, both months exhibit similar temperature ranges, with September having a minimum of 8°C (47°F) and an average of 20°C (69°F), while June starts slightly higher with a minimum of 9°C (49°F) and an average of 21°C (71°F). The maximum temperatures peak at 33°C (91°F) in September and slightly higher at 34°C (93°F) in June. In terms of precipitation, September experiences a bit more rain, with 98 mm (3.8 in) over 9 days compared to June's 91 mm (3.6 in) over 12 days. Humidity levels are fairly close, with September averaging 68% and June at 69%. For a closer look at June's weather specifics, you can check out Greenwich weather in June.
In comparing the weather between September and July, September offers a wider temperature range with minimums dropping to 8°C (47°F) compared to July's 16°C (60°F). While both months can experience warm days, September's average temperature of 20°C (69°F) is notably cooler than July's warmer average of 25°C (77°F). July also boasts a higher maximum temperature, reaching up to 35°C (96°F), whereas September's maximum can go up to 33°C (91°F). In terms of precipitation, July is wetter with 143 mm (5.6 in) falling over 13 days, in contrast to September’s 98 mm (3.8 in) over 9 days. Interestingly, September's humidity sits at 68%, slightly higher than July's 62%. For more details on July's weather, you can visit Greenwich weather in July.
In comparing the weather between August and September, we see a notable shift in temperatures and precipitation patterns. September experiences cooler temperatures with a minimum of 8°C (47°F) and an average of 20°C (69°F), whereas August has a milder minimum of 15°C (59°F) and an average of 24°C (75°F). The maximum temperature in September peaks at 33°C (91°F), similar to August's high of 34°C (93°F). However, September is slightly wetter, receiving 98 mm (3.8 in) of precipitation over 9 days compared to August's 123 mm (4.8 in) across 14 days. Additionally, September sees a higher humidity level at 68% versus August's 65%. For a detailed look at August conditions, visit Greenwich weather in August.
September and October showcase a noticeable shift in weather patterns. September sees a wider temperature range, with minimums around 8°C (47°F) and maximums reaching up to 33°C (91°F), resulting in a comfortable average of 20°C (69°F). In contrast, October's temperatures drop, featuring a minimum of 3°C (38°F) and an average of 15°C (60°F), with maximums slightly lower at 32°C (90°F). Precipitation increases from 98 mm (3.8 in) over 9 days in September to 132 mm (5.2 in) over 11 days in October, accompanied by a rise in humidity from 68% to 74%. For more detailed information, check out Greenwich weather in October.
September typically experiences much warmer weather compared to November, with average temperatures reaching around 20°C (69°F) and a maximum of 33°C (91°F), while November sees a significant drop, with an average of 8°C (46°F) and a maximum of 23°C (74°F). Additionally, September is marked by relatively lower humidity levels at 68%, contrasting with November's higher humidity of 82%. Precipitation levels are fairly similar between the two months, with September receiving 98 mm (3.8 in) and November recording 86 mm (3.4 in) of rainfall over the same number of days. To learn more about weather specifics in November, you can visit Greenwich weather in November.
In September, temperatures are generally much warmer, ranging from a minimum of 8°C (47°F) to a pleasant average of 20°C (69°F) and peaking at 33°C (91°F). The month sees an average precipitation of 98 mm (3.8 in) over about 9 days, with humidity levels around 68%. In contrast, December brings a significant drop in temperatures, with lows plunging to -12°C (11°F) and an average of just 3°C (38°F), reaching a maximum of 17°C (63°F). Rainfall slightly increases in December, totaling 111 mm (4.4 in) across 11 days, accompanied by higher humidity levels at 80%. For more details on the December weather, you can access Greenwich weather in December.
As summer transitions into autumn, September in Greenwich brings a distinct shift in weather patterns. With comfortable average temperatures hovering around 20°C (69°F), the month offers a refreshing respite from the peak summer heat, where maximum temperatures can occasionally soar to 33°C (91°F). Rainfall becomes more frequent, with 9 days of precipitation contributing to a total of 98 mm (3.8 in), which helps nurture the vibrant fall foliage. Meanwhile, humidity levels averaging 68% can add a touch of mugginess on warmer days, contrasting with the crispness that typically characterizes October. To explore more about how September weather shapes the unique climate of Greenwich, check out Greenwich Climate.