Last updated: February 24, 2025
In September, Port Jefferson experiences a pleasant transition into fall, with maximum temperatures reaching up to 30°C (87°F) and an average of 21°C (70°F). The minimum temperatures dip to a cool 11°C (52°F), making it an ideal time for outdoor activities. This month also sees 94 mm (3.7 in) of rain spread over 10 days, contributing to a humidity level of 68%, which can create a refreshing atmosphere along the coastline. Overall, September offers a delightful blend of warm days and cooler evenings, perfect for enjoying the changing seasons.
In September, Port Jefferson enjoys a pleasant transition from the heat of summer to the crispness of autumn. With minimum temperatures around 11°C (52°F) and average highs reaching 30°C (87°F), the month is characterized by warm, inviting days perfect for outdoor activities. As summer's warmth lingers, the average temperature settles around 21°C (70°F), making it an ideal time for beach outings and leisurely strolls. This month marks a notable shift from the steamy peak of August, offering a delightful blend of warmth and comfort that encourages both locals and visitors to revel in the town's scenic beauty. With the sun shining brightly yet softened by the onset of fall, September in Port Jefferson truly embodies the best of both seasons.
In September, Port Jefferson experiences a moderate shift in its precipitation patterns, with a total of 94 mm (3.7 in) of rainfall spread across 10 days. This marks a slight decrease from the wetter months of July and August, which recorded 131 mm (5.2 in) and 103 mm (4.0 in) respectively. The transition into autumn is evident as September's rainfall prepares the landscape for the upcoming season, making it the sixth wettest month of the year. Overall, September's precipitation hints at a lingering summer warmth while subtly ushering in the cooler, more rain-prone months ahead, particularly October, which averages 143 mm (5.6 in). The moderate rainfall and fewer rainy days create a balanced climate, perfect for the gradual shift in foliage and seasonal change.
In September, Port Jefferson experiences a slight uptick in humidity, averaging around 68%, which marks a gentle transition from the summer months. This figure, while lower than the peak of 69% in June and July, reflects a gradual decrease in moisture levels that began in May. As the year progresses, humidity begins to creep higher again in the fall, with October showing a notable rise to 74%. Overall, the trend highlights Port Jefferson's characteristic shift from the sticky summer climate towards the milder and crisper conditions of autumn, making September a month of pleasant balance before the humidity returns in November.
As September rolls in, Port Jefferson experiences a slight dip in the UV Index, settling at 8, which still falls within the very high exposure category. This trend continues the elevated UV levels seen throughout the summer months, where consistent readings of 9 to 10 were the norm. With a burn time of just 15 minutes, it’s essential for residents and visitors to remain vigilant about sun protection even as the seasons begin to change. Compared to the earlier spring months, where the Index ranged from 3 to 6, September's UV intensity underscores the lingering strength of the sun. For more details and to plan your sun safety, check out the Port Jefferson UV Index.
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As the summer wanes, September in Port Jefferson continues to bask in the warm glow of sunshine, offering an impressive 282 hours of sunlight. This marks a gentle decline from the peak of 343 hours in July but remains significantly brighter than the earlier months of the year. The gradual shift from the summer’s abundance is mirrored in October's forecasted 225 hours, hinting at the impending embrace of fall. With each passing month, residents and visitors alike can savor the rich tapestry of seasonal changes, from the vibrant summer days to the mellow autumn hues, making September a splendid time to enjoy outdoor activities before the cooler weather sets in.
In Port Jefferson, September offers a refreshing transition as the summer warmth begins to wane. With a 48% chance of sunny weather, the likelihood remains steady compared to the earlier months, showcasing a summer-like vibe even as autumn approaches. Interestingly, this figure aligns closely with the preceding month of August at 32%, which hints at the lingering sunshine. However, as we transition into October, the sun’s presence tends to dip again, dropping to 41%. This September sunny weather trend indicates a delightful opportunity for outdoor activities, making it an admirable choice for those looking to bask in the early fall glow before the clouds of winter set in.
As September rolls around in Port Jefferson, the daylight hours begin to slightly wane, settling at 12 hours. This marks a gentle transition from the peak summer months, where long days of 15 hours in June bathe the landscape in sunlight, to the crisp, shorter days of autumn ahead. Notably, this month sees a decline from the 13 hours enjoyed in August, signaling a gradual shift into fall. The daylight duration in September reflects a steady pattern throughout the year: the days lengthen from winter's grip in January, reaching their zenith mid-year, before gradually retreating as the year draws to a close. Such cyclical changes not only highlight the rhythm of the seasons but also set the stage for the vibrant colors and cooler temperatures that autumn promises.
As summer gives way to autumn, September in Port Jefferson experiences a refreshing shift in wind patterns, with an average wind speed of 4.3 m/s (10 mph)—a noticeable increase from the calmer conditions of July and August, when winds slowed to 3.4 m/s (8 mph). This return to slightly brisker winds signals the seasonal transition, as it is comparable to the spring months of April and May. As October approaches, wind speeds rise further to 4.7 m/s (10 mph), preparing the landscape for the invigorating gusts that define the fall. Overall, September serves as a bridge, marking the end of summer's softness and ushering in the crisper winds of the approaching season.
The weather in Port Jefferson 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 Port Jefferson and find detailed weather information for every month.
September weather in Port Jefferson features a warm range, with temperatures typically varying from a mild 11°C (52°F) at night to a pleasant average of 21°C (70°F) and occasionally peaking at 30°C (87°F). This month also experiences about 94 mm (3.7 in) of rain over approximately 10 days, with a humidity level of 68% contributing to a comfortable, late-summer atmosphere. In contrast, January brings a stark chill, with temperatures dipping to a minimum of -15°C (6°F), averaging only 2°C (35°F), and not exceeding 15°C (60°F). January also sees a bit less rainfall at 80 mm (3.1 in) across 8 days, but the humidity is notably higher at 84%, which can intensify the cold feeling. For more details on January weather, visit Port Jefferson weather in January.
September and February present starkly contrasting weather conditions. In September, temperatures range from a pleasant minimum of 11°C (52°F) to a warm maximum of 30°C (87°F), with an average of 21°C (70°F). The month sees moderate precipitation totaling 94 mm (3.7 in) over about 10 days, coupled with a humidity level of 68%. In contrast, February experiences much colder temperatures, with a minimum of -15°C (6°F) and a maximum of 15°C (58°F), resulting in an average temperature of just 2°C (36°F). The month is wetter, characterized by 112 mm (4.4 in) of precipitation over 12 days and higher humidity at 82%. For a closer look at February's conditions, check out Port Jefferson weather in February.
When comparing the weather in September and March, notable differences emerge. September typically boasts warmer temperatures with a minimum of 11°C (52°F) and an average temperature of 21°C (70°F), peaking at 30°C (87°F). In contrast, March experiences much cooler conditions, with a minimum of -8°C (17°F) and an average temperature of just 4°C (40°F), reaching a maximum of 19°C (67°F). Additionally, while both months see around 10 days of precipitation, September receives 94 mm (3.7 in), slightly less than March’s 104 mm (4.1 in). Humidity is also higher in March at 81%, compared to September’s 68%. For more detailed insights into the weather specifics of March, you can visit Port Jefferson weather in March.
In comparing the weather conditions of September and April, it's clear that September tends to be warmer and drier. In September, temperatures typically range from a minimum of 11°C (52°F) to a maximum of 30°C (87°F), with an average of 21°C (70°F) and only 94 mm (3.7 in) of precipitation over approximately 10 days. Conversely, April experiences cooler temperatures, with a range from -1°C (31°F) to 22°C (71°F), and a lower average of 9°C (49°F). Additionally, April sees more precipitation, totaling 132 mm (5.2 in) over 12 days, and higher humidity at 78%. For more detailed insights on April weather, you can check out Port Jefferson weather in April.
In comparing the weather of September and May, we see notable differences in temperature and precipitation. September enjoys warmer temperatures, with averages around 21°C (70°F) and highs reaching up to 30°C (87°F), while May presents cooler conditions, with an average of 14°C (58°F) and a maximum of 26°C (79°F). Despite being warmer, September experiences slightly less precipitation, totaling 94 mm (3.7 in) over about 10 days, compared to May's 119 mm (4.7 in) spread across 13 rainy days. Additionally, both months share similar humidity levels, hovering around 68-69%. For a closer look at May's weather specifics, you can visit Port Jefferson weather in May.
In comparing the weather conditions of September and June, we see some subtle yet notable differences. September boasts a slightly higher average maximum temperature of 30°C (87°F) compared to June's maximum of 29°C (85°F), making it feel a tad warmer as summer winds down. Both months experience similar humidity levels, with September at 68% and June slightly higher at 69%. However, September has more precipitation, totaling 94 mm (3.7 in) over about 10 days, while June sees a bit less rain at 87 mm (3.4 in) over 9 days. For a closer look at June's climate specifics, check out Port Jefferson weather in June.
In comparing the weather between September and July, September typically presents a milder climate with temperatures ranging from a minimum of 11°C (52°F) to a maximum of 30°C (87°F), averaging around 21°C (70°F). It has a higher humidity level at 68% but experiences less rainfall overall, with 94 mm (3.7 in) of precipitation over about 10 days. In contrast, July enjoys warmer conditions with temperatures from a minimum of 16°C (60°F) to a maximum of 33°C (91°F), averaging 24°C (76°F). This month also sees more rainfall, totaling 131 mm (5.2 in) across 12 days, but with slightly lower humidity at 62%. For more detailed insights, you can check Port Jefferson weather in July.
In comparing the weather between September and August, September experiences a more moderate temperature range with minimums of 11°C (52°F) and maximums of 30°C (87°F), while August has higher minimums at 16°C (61°F) and slightly higher maximums at 31°C (88°F). The average temperatures in September, at 21°C (70°F), are cooler than August's average of 24°C (75°F). Additionally, September sees a total precipitation of 94 mm (3.7 in) over 10 days, compared to August's 103 mm (4.0 in) over 11 days. Interestingly, while September's humidity is a bit higher at 68%, August maintains a slightly lower level at 65%. For a deeper look at conditions during August, you can visit Port Jefferson weather in August.
September and October bring noticeable shifts in weather patterns. In September, temperatures range from a minimum of 11°C (52°F) to a maximum of 30°C (87°F), with an average of 21°C (70°F) and 94 mm (3.7 in) of precipitation over approximately 10 days. The humidity sits at 68%, providing warm and relatively comfortable days. In contrast, October sees a drop in average temperatures to 16°C (61°F), with minimums dipping to 5°C (41°F) and maximums reaching 29°C (84°F). Precipitation increases to 143 mm (5.6 in) over 12 days, accompanied by higher humidity levels at 74%. This transition marks a shift towards cooler and wetter conditions. For more details, check out Port Jefferson weather in October.
In September, temperatures are generally warm, with a minimum of 11°C (52°F) and an average high of 30°C (87°F), making it a pleasant month for outdoor activities. However, the weather can also be quite humid, with a humidity level of 68% and an average of 94 mm (3.7 in) of precipitation over about 10 days. In contrast, November experiences much cooler temperatures, with minimums dropping to -6°C (21°F) and averaging around 9°C (49°F), while the maximum temperature remains the same at 21°C (70°F). November also sees a slight increase in precipitation to 103 mm (4.0 in), though it occurs over just 9 days, and the humidity rises to 82%. For more details on November weather, visit Port Jefferson weather in November.
September and December present starkly contrasting weather conditions. In September, temperatures range from a mild 11°C (52°F) at night to a warm 30°C (87°F) during the day, with an average of 21°C (70°F). The month experiences a moderate 94 mm (3.7 in) of precipitation over approximately 10 days, accompanied by a humidity level of 68%. In contrast, December brings much colder temperatures, with a minimum of -10°C (15°F) and a maximum of 17°C (62°F), averaging only 5°C (40°F). The month is wetter, with precipitation reaching 140 mm (5.5 in) over 11 days and higher humidity at 80%. For more details on December weather, you can visit Port Jefferson weather in December.
As September unfolds in Port Jefferson, it ushers in a transition from the warmth of summer to the crispness of autumn. You can expect pleasantly mild days with an average temperature around 21°C (70°F), contrasting the sweltering peaks reached in July and August. While the humidity remains a lingering presence at 68%, it offers a refreshing change from the more oppressive levels of summer. The month also brings about the shift in precipitation patterns, with 10 days of rainfall totaling 94 mm (3.7 in), suggesting a more dynamic climate as the season progresses. For a deeper dive into Year-round weather variations, explore Port Jefferson Climate.