September Weather in New Castle, United States

Last updated: February 24, 2025

In September, New Castle, United States, experiences a delightful transition into fall, marked by an average temperature of 18°C (65°F). The maximum temperature can reach up to 30°C (86°F), while nights cool down to a cozy minimum of 7°C (46°F). With humidity levels hovering around 71%, the air feels comfortably mild. Although the region sees about 78 mm (3.1 in) of precipitation spread over 8 days, these occasional showers often enhance the vibrant autumn scenery, making September a picturesque time to explore the area.

September Temperature in New Castle

In September, New Castle experiences a delightful transition as summer gives way to fall. The temperatures start to cool, with minimum values around 7°C (46°F) and a pleasant average reaching 18°C (65°F), making it a comfortable time for outdoor activities. The warm maximum temperature of 30°C (86°F) still lingers, allowing for those final sun-soaked days before the chilly air settles in for the autumn months. This month serves as a perfect reminder of the warmth of summer while hinting at the cooler days to come, making it an ideal time for both exploration and relaxation in this vibrant region.

September Weather in New Castle: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in New Castle, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec303236465565717165554334
Data source: Temperature data for New Castle 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 New Castle

In September, New Castle experiences a moderate precipitation level with 78 mm (3.1 in) of rainfall spread across 8 days. This marks a slight decline from the summer's heavier rains, particularly July's 123 mm (4.8 in), suggesting a transition towards drier autumn months. Interestingly, September's rainfall is comparable to the previous month, August, which recorded only 71 mm (2.8 in) over 9 days. This pattern reflects a gradual decrease in precipitation as the seasons change, paving the way for more substantial rains in October, with an expected 142 mm (5.6 in). Overall, September serves as a bridge between the lush, wet summer and the forthcoming autumnal deluge, offering a hint of what’s to come.

September Precipitation Trends in New Castle

The chart displays monthly precipitation patterns in New Castle, 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.
JanFebMarAprMayJunJulAugSepOctNovDec79989414383881237178143108133
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in New Castle

As summer fades and autumn approaches in New Castle, September experiences a modest rise in humidity, with levels averaging 71%. This marks a slight increase from August's 66%, reflecting the transition from the drier summer months. Interestingly, the humidity begins its gradual climb again after hitting a low point in July and August, making September feel less oppressive than the peak summer heat, yet still reminding residents of the moisture-laden months that lie ahead. This cyclical pattern suggests that as New Castle moves towards the cooler months, the air becomes more saturated, setting the stage for the wetter conditions often characteristic of fall.

September Average Humidity in New Castle

This chart illustrates the average monthly humidity levels in New Castle, 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 New Castle

As September rolls into New Castle, the UV Index reflects a significant drop from the summer months, settling at a high level of 7. While still indicative of strong sun exposure, this marks a shift from the peak very high readings of 9 and 10 experienced in July and August. With a burn time of 25 minutes, residents and visitors should remain cautious, embracing sun safety measures while enjoying the outdoor activities that early autumn offers. This transition into fall reminds us of the importance of monitoring UV levels year-round, especially as they fluctuate through the seasons. For more detailed insights on UV exposure, visit New Castle UV Index.

Maximum UV Index Levels in New Castle for September

The chart shows the monthly maximum UV Index (UVI) for New Castle 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.
JanFebMarAprMayJunJulAugSepOctNovDec2457910997532
Data source: New Castle 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 New Castle

As summer fades, September in New Castle continues to bask in the warmth of sunshine, offering an impressive 285 hours of bright days. This marks a slight decline from the striking peak of 337 hours experienced in August, yet it remains significantly higher than the winter months such as January, which only boasts 150 hours. Notably, September's sunshine plays a pivotal role in easing the transition into autumn, balancing daily warmth with the beginnings of cooler breezes. With daylight hours steadily decreasing as the year progresses, this month still provides ample opportunity to soak up the lingering summer rays before they retreat. Overall, September shines as a beautiful connector between the vitality of summer and the comforting embrace of fall.

Monthly Sunshine Duration in New Castle: September Highlighted

The September sunshine duration represents the total number of hours New Castle 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.
JanFebMarAprMayJunJulAugSepOctNovDec150h183h256h245h295h330h335h337h285h221h193h176h
Data source: New Castle September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in New Castle During September

In September, New Castle, United States, experiences a 44% chance of sunny weather, making it one of the more favorable months for sunshine as summer transitions into fall. While the likelihood of sun is higher than during the peak summer months of July and August, which see only 32%, it still lags behind the promising 61% chance found in March. Overall, September stands out as a month of potential brightness amid a backdrop of fluctuating weather patterns throughout the year, suggesting that visitors and locals alike can expect a mix of sun and clouds as autumn begins to unfold.

Percentage of Sunny Days in September in New Castle

The chart illustrates the percentage of sunny days in New Castle 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 New Castle experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec42%35%61%40%38%40%32%32%44%38%54%32%
Data source: New Castle September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in New Castle in September

In September, New Castle experiences a noticeable shift in daylight, with the duration settling at 12 hours. This marks a decline from the 14 hours in May and 15 hours in June, illustrating the transition from the longer days of summer to the shorter days of fall. As the year progresses, daylight steadily decreases, dropping to 10 hours by October and maintaining a 9-hour limit through the winter months of November and December. This rhythm of daylight not only reflects changing seasons but also influences the daily activities and moods of the community, inviting a blend of outdoor adventures and cozy indoor gatherings as summer gives way to autumn.

Average Daylight Hours in New Castle for September

The chart illustrates the variation in daylight duration in New Castle throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 23m10h 31m11h 57m13h 26m14h 40m15h 18m14h 57m13h 51m12h 26m10h 58m9h 41m9h 2m
Data source: New Castle daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in New Castle

As September rolls in, New Castle experiences a subtle shift in its wind patterns, with an average wind speed of 3.9 m/s (9 mph). While this marks a slight uptick from the laziness of summer, where winds dropped to a gentle 3.3 m/s (7 mph) in August, the breezes remain relatively mild compared to earlier months. Interestingly, the spring months started off robust, peaking at 5.2 m/s (12 mph) in March, before gradually declining through the summer. Now, as autumn approaches, one can feel the refreshing whispers of September winds, hinting at the seasonal transitions ahead, which will soon bring increased gusts in October. This gradual shift in wind speed not only reflects the changing season but also sets the stage for the refreshing breezes of fall, inviting residents to embrace the new atmospheric rhythm.

Average September Wind Speed in New Castle

The chart displays monthly wind speed patterns in New Castle, 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.
JanFebMarAprMayJunJulAugSepOctNovDec4.74.75.24.44.24.13.53.33.9 m/s4.44.64.6
Data source: New Castle September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in New Castle Compares to Other Months

The weather in New Castle 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 New Castle and find detailed weather information for every month.

September and January showcase starkly contrasting weather conditions. In September, temperatures range from a mild 7°C (46°F) to a warm 30°C (86°F), with an average of 18°C (65°F), while January's temperatures plummet to a minimum of -19°C (-2°F) and a maximum of 17°C (64°F), averaging around -1°C (30°F). Both months see similar precipitation levels, at 78-79 mm (3.1 in) over approximately 8 days, but January's higher humidity at 86% contributes to a noticeably colder feel compared to September's 71% humidity. For a detailed look at January weather, visit New Castle weather in January.

September and February present stark contrasts in weather conditions. In September, temperatures range from a milder minimum of 7°C (46°F) to a warm maximum of 30°C (86°F), with an average of 18°C (65°F). The month experiences moderate rainfall, totaling 78 mm (3.1 in) over about 8 days, accompanied by a humidity level of 71%. In contrast, February showcases much colder temperatures, with a minimum of -16°C (4°F) and a maximum reaching only 17°C (64°F), averaging around 0°C (32°F). This month also sees increased precipitation of 98 mm (3.9 in) over approximately 11 days, coupled with high humidity at 84%. For more details on the February weather in New Castle, you can check New Castle weather in February.

When comparing the weather of September and March, it's evident that these months present stark contrasts. September enjoys milder temperatures with a minimum of 7°C and an average reaching 18°C, peaking at 30°C, while March is significantly colder, with a minimum of -14°C and an average temperature of only 2°C, though it can rise to 17°C at times. Precipitation is more frequent in March with 94 mm over 10 days compared to September's 78 mm over 8 days, which contributes to a higher humidity level of 82% in March versus 71% in September. For a closer look at the specifics, you can check New Castle weather in March.

In comparing the weather conditions of September and April, we see notable differences in temperature and precipitation. September enjoys milder temperatures, with averages around 18°C (65°F) and maximums reaching up to 30°C (86°F), while April experiences cooler averages of 8°C (46°F), with maximums only peaking at 24°C (76°F). Additionally, April tends to be wetter, receiving about 143 mm (5.6 in) of precipitation over 13 days, compared to September's 78 mm (3.1 in) over just 8 days. Both months have relatively high humidity, with April slightly higher at 80% compared to September's 71%. For more detailed information, you can refer to New Castle weather in April.

In September, temperatures can range from a chilly 7°C (46°F) at night to a warm 30°C (86°F) during the day, resulting in a comfortable average of 18°C (65°F). The month experiences about 78 mm (3.1 in) of precipitation over roughly 8 days, with humidity hovering around 71%. In contrast, May features cooler temperatures, with a minimum of 2°C (37°F), an average of 13°C (55°F), and a maximum of 27°C (82°F). It sees slightly higher precipitation at 83 mm (3.3 in) across 11 days, while humidity levels are marginally higher at 72%. For more details, check New Castle weather in May.

When comparing the weather in September and June, both months exhibit similar temperature ranges, with minimums hovering around 7-8°C (46-47°F) and maximums reaching up to 30°C (86°F). The average temperature remains consistent at 18°C (65°F) in both months. However, September experiences slightly less precipitation at 78 mm (3.1 in) over about 8 days, compared to June's 88 mm (3.5 in) over approximately 10 days. Humidity levels are also quite close, with September at 71% and June at 72%. For a more detailed look at June's weather specifics, check out New Castle weather in June.

In comparing the weather of September and July, it is evident that July tends to be warmer overall, with average temperatures reaching 22°C (71°F) and a maximum high of 31°C (88°F). In contrast, September has a lower average temperature of 18°C (65°F), with maximums reaching up to 30°C (86°F). While July experiences a higher minimum temperature of 13°C (56°F), September's cooler nights can drop as low as 7°C (46°F). Precipitation is also more prevalent in July, with 123 mm (4.8 in) of rain over 12 days compared to September's 78 mm (3.1 in) over 8 days; however, September has a slightly higher humidity at 71% versus July's 67%. For more detailed insights, you can check New Castle weather in July.

In comparison to August, September typically experiences cooler temperatures, with a minimum of 7°C (46°F) and an average of 18°C (65°F) compared to August's minimum of 13°C (55°F) and average of 22°C (71°F). Both months feature similar maximum temperatures, with September peaking at 30°C (86°F) and August at 31°C (88°F), but September tends to have slightly more rainfall, with 78 mm (3.1 in) across 8 days compared to August's 71 mm (2.8 in) over 9 days. Additionally, September has higher humidity at 71%, while August maintains a lower humidity level of 66%. For more details about August weather patterns, you can check New Castle weather in August.

September and October bring distinct changes in weather as summer transitions into fall. In September, temperatures range from a minimum of 7°C (46°F) to a maximum of 30°C (86°F), with an average of 18°C (65°F). The month experiences moderate rainfall, totaling 78 mm (3.1 in) over about 8 days, accompanied by a humidity level of 71%. In contrast, October sees a significant drop in temperatures, with a minimum of 1°C (34°F) and an average of 13°C (56°F), peaking at 25°C (78°F). Rainfall increases to 142 mm (5.6 in), spread across 11 days, and humidity rises slightly to 78%. For more details on October weather, visit New Castle weather in October.

The weather in September is characterized by a more moderate temperature range, with minimums around 7°C (46°F) and maximums reaching up to 30°C (86°F), making it a pleasant month for outdoor activities. In contrast, November sees a notable drop in temperatures, with minimums dipping to -12°C (11°F) and a cooler average of 6°C (43°F). Additionally, November experiences more precipitation, with 108 mm (4.3 in) over 11 days compared to September's 78 mm (3.1 in) over 8 days. The increase in humidity from 71% in September to 84% in November further emphasizes the transition into the chillier late fall season. For more detailed insights, you can check New Castle weather in November.

In comparing the weather of September and December, there's a striking contrast. September boasts a comfortable average temperature of 18°C (65°F), with maximum highs reaching up to 30°C (86°F), while December's average drops significantly to just 1°C (34°F), with lows plunging to -19°C (-1°F). Additionally, December experiences more precipitation, totaling 133 mm (5.2 in) over 10 days, compared to September's 78 mm (3.1 in) across 8 days. Humidity also rises slightly in December to 81%, compared to September's 71%. This dramatic shift not only highlights the transition from a warm late summer to a cold winter but also underscores the necessity of adjusting to the colder climate, as detailed in New Castle weather in December.

Compare New Castle's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in New Castle

September in New Castle marks a transition into cooler temperatures and a unique blend of warm days and crisp nights. Unlike the summer months that boast consistent heat, September offers a refreshing dip in temperatures, making outdoor activities more enjoyable. While the humidity remains a bit high, the relatively low precipitation allows residents and visitors alike to make the most of this delightful month. Despite the occasional rain, the distinct character of September often draws people outside to relish the beautiful scenery. For a comprehensive overview of how September’s weather fits into the overall patterns, check out the New Castle Climate.