September Weather in North, United States

Last updated: February 24, 2025

In September, the northern United States experiences varying weather conditions marked by a maximum temperature reaching 37°C (99°F), while the average settles around a comfortable 25°C (78°F). Nighttime sees a drop to a refreshing minimum of 11°C (52°F). Although the month brings pleasant warmth, it is also characterized by notable precipitation, accumulating 95 mm (3.7 in) over 9 days, resulting in a humid environment with an average humidity of 83%. This blend of heat and moisture creates a dynamic atmosphere, setting the stage for both vibrant autumnal colors and frequent rain showers.

September Temperature in North

In September, the North of the United States experiences a notable shift as summer gradually transitions into fall. With a minimum temperature of 11°C (52°F) and an average of 25°C (78°F), the warmth lingers, making it one of the last months to enjoy fairly mild weather before cooler temperatures take hold. The maximum temperature can reach up to 37°C (99°F), hinting at the tail end of summer’s heat. This transitional month reflects a comforting balance as nature prepares for the impending chill of October while still offering plenty of pleasant days, making it an ideal time for outdoor activities and harvest festivals.

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

The chart illustrates September temperature patterns in North, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec495559667479828177705652
Data source: Temperature data for North 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 North

In September, the North United States experiences a notable shift in precipitation patterns, with 95 mm (3.7 in) of rain spread across 9 days. This marks a decline from August's heavier rainfall of 148 mm (5.8 in) over 18 days, suggesting the end of summer storms as the region transitions into autumn. The decrease in both total rainfall and precipitation days indicates a trend towards drier conditions, which will continue into October, where averages drop further to 69 mm (2.7 in). This seasonal transformation not only underscores the changing weather patterns but also sets the stage for the crisp, cooler days ahead, as nature prepares for a shift in its annual rhythm.

September Precipitation Trends in North

The chart displays monthly precipitation patterns in North, 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.
JanFebMarAprMayJunJulAugSepOctNovDec809980116104122157148956962129
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in North

As summer gives way to fall, September ushers in a slight rise in humidity across the northern United States, reaching an average of 83%. This marks a modest increase from the 81% humidity experienced in August, suggesting a lingering warmth as temperatures begin to cool. Trends throughout the year show that late summer maintains relatively high humidity levels, peaking in winter months with January's 86%. The gradual decline in humidity from late spring through early summer reflects the region's transitional climate, but September’s uptick hints at the last vestiges of summer's warmth, setting the stage for the cooler, crisper air of autumn. As October approaches, a drop to 78% is anticipated, continuing the seasonal rhythm of shifting humidity patterns.

September Average Humidity in North

This chart illustrates the average monthly humidity levels in North, 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%81%81%79%75%75%80%81%83%78%85%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in North

As September arrives in the North United States, the UV Index reflects a notable decline from the summer's peak, settling at 9, categorized as very high. This marks a slight decrease from the extreme levels seen in July and August, where the UV Index remained at a consistent 11. Despite this reduction, September still demands attention, with a burn time of just 15 minutes for those unprotected by sunscreen. As fall approaches, it's essential to adapt your sun safety practices, recognizing that while temperatures may drop, the sun's intensity can still pose a significant risk. For a deeper understanding of UV exposure risks throughout the year, explore the comprehensive data available at North UV Index.

Maximum UV Index Levels in North for September

The chart shows the monthly maximum UV Index (UVI) for North 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.
JanFebMarAprMayJunJulAugSepOctNovDec47810111111119864
Data source: North 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 North

As the warm embrace of summer begins to wane, September in the northern United States shines brightly with an impressive 294 hours of sunshine. This month marks a gentle decline from the peak 344 hours basked in during July, yet it still generously offers more daylight than the cooler months that follow. The transition from summer to fall is evident, as September retains a reassuring amount of sunlight, outshining October and November, which further exhibit the gradual descent into shorter days. The steady increase in sunshine hours from January's 174 to September's sunny skies highlights the slow but rewarding progression towards the vibrant hues of autumn, where each sunny day invites outdoor exploration before winter's chill sets in.

Monthly Sunshine Duration in North: September Highlighted

The September sunshine duration represents the total number of hours North 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.
JanFebMarAprMayJunJulAugSepOctNovDec174h187h256h290h312h314h344h311h294h281h242h206h
Data source: North September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in North During September

As summer transitions into autumn, the likelihood of sunny weather in September in the northern United States offers a refreshing shift. With a 51% chance of sunshine, September stands out as one of the more promising months for clear skies, especially when compared to the dreariness of June and July, which only boast 30% and 34% sunny days, respectively. This uptick in sunshine is mirrored in the gradual rise of probabilities through the spring months leading into early fall, particularly from April's 56% to October's 48%. Interestingly, September serves as a bridge, offering a blend of summer warmth and early autumn charm, setting the stage for delightful outdoor activities before the colder months roll in.

Percentage of Sunny Days in September in North

The chart illustrates the percentage of sunny days in North 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 North experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec45%36%37%56%47%30%34%37%51%49%65%40%
Data source: North September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in North in September

As September unfolds in the northern United States, daylight begins a subtle yet noticeable decline, averaging 12 hours of sunlight. Following the peak of 14 hours in June and July, the daylight hours gradually taper off, signaling the imminent arrival of autumn. The shift from summer's abundance to early fall is marked by a delicate balance, with only slight differences in daylight compared to the preceding months. As the leaves start to change color and the air turns crisp, the transition towards shorter days becomes an invitation to embrace cozy evenings and the beauty of the season ahead.

Average Daylight Hours in North for September

The chart illustrates the variation in daylight duration in North throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 12m10h 59m11h 59m13h 1m13h 53m14h 19m14h 5m13h 19m12h 19m11h 18m10h 24m9h 57m
Data source: North daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in North

As September unfolds in the northern United States, the winds transition gently from the summer's calm breath. With an average wind speed of 2.4 m/s (5 mph), September marks a slight uptick from August's lull. This month continues the trend of diminishing gusts observed from the early spring months, where winds were consistently stronger—peaking at 3.6 m/s (8 mph) in March. As autumn approaches, we can see a gradual recovery in wind speeds toward October, hinting at the spirited breezes that will soon accompany the changing leaves. Wind patterns suggest a seasonal shift, fueling anticipation for the invigorating winds of fall that will soon sweep through the region.

Average September Wind Speed in North

The chart displays monthly wind speed patterns in North, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.43.33.63.43.22.82.52.22.4 m/s2.83.33.2
Data source: North September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in North Compares to Other Months

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

September and January exhibit stark contrasts in weather patterns. In September, temperatures can range from a mild 11°C (52°F) at night to a scorching average high of 37°C (99°F), with high humidity at 83% contributing to a muggy atmosphere. Precipitation is moderate, averaging 95 mm (3.7 in) over about 9 days. In contrast, January presents a much colder climate, with temperatures dropping to a minimum of -9°C (17°F) and peaking at a comfortable 27°C (80°F). Precipitation decreases slightly to 80 mm (3.1 in), falling over around 8 days, while humidity remains relatively high at 86%. For more insights into the January climate, visit North weather in January.

September and February present contrasting weather patterns. In September, temperatures range from a comfortable 11°C (52°F) at night to a scorching 37°C (99°F) during the day, with an average of 25°C (78°F). This month also experiences significant rainfall, totaling 95 mm (3.7 in) over 9 days, coupled with high humidity at 83%. In sharp contrast, February sees chillier conditions, with nighttime lows dropping to -5°C (23°F) and daytime highs peaking at 29°C (85°F), averaging 13°C (55°F). Precipitation is slightly higher in February at 99 mm (3.9 in) over 10 days, but the humidity remains relatively lower at 81%. For more detailed information, you can visit North weather in February.

September experiences considerably warmer temperatures compared to March, with average highs reaching up to 37°C (99°F) and a minimum of 11°C (52°F), which creates a much more humid atmosphere with 83% humidity. In contrast, March sees significantly cooler temperatures, with an average high of 32°C (90°F) and a minimum dropping to -4°C (24°F), accompanied by slightly lower humidity at 81%. While both months see a similar amount of precipitation, September is slightly wetter, receiving 95 mm (3.7 in) over 9 days compared to March's 80 mm (3.1 in) over 10 days. For more information about the weather, check out North weather in March.

In comparing September and April weather, September tends to be warmer, with average temperatures around 25°C (78°F) and maximums reaching up to 37°C (99°F), whereas April has a milder average temperature of 19°C (66°F) and maximums peaking at 33°C (92°F). Additionally, September experiences higher humidity levels at 83%, compared to 79% in April. Rainfall in April is slightly higher, with 116 mm (4.6 in) over 8 days, while September sees 95 mm (3.7 in) across 9 days. For more details on April weather, you can check this link: North weather in April.

When comparing the weather in September and May, it's clear that both months experience warm temperatures, although September tends to be slightly warmer overall. September's average temperature reaches around 25°C (78°F), with a maximum of 37°C (99°F), while May has a lower average temperature of 23°C (74°F) but can peak at 38°C (101°F). Both months see similar amounts of precipitation, with September receiving 95 mm (3.7 in) and May slightly more at 104 mm (4.1 in), and both months also experience rain on approximately nine days. However, September is noticeably more humid at 83% compared to May's 75%. For those interested in a deeper dive into May's conditions, you can refer to North weather in May.

September typically experiences slightly lower temperatures than June, with average highs around 25°C (78°F) compared to June's 26°C (79°F). However, June can reach higher peaks, with maximum temperatures hitting 39°C (102°F), compared to September's 37°C (99°F). Despite the similar temperature ranges, June sees more precipitation, averaging 122 mm (4.8 in) over 14 days, whereas September has 95 mm (3.7 in) over 9 days. Interestingly, humidity levels are higher in September at 83%, compared to June's 75%. For more insights on this month's weather characteristics, you can check out North weather in June.

In comparing the weather between September and July, September generally presents a more varied temperature range, with a minimum of 11°C (52°F) and a maximum of 37°C (99°F), while July tends to be warmer, with minimums of 16°C (61°F) and maximums reaching 38°C (101°F). July also experiences significantly higher precipitation, totaling 157 mm (6.2 in) over 17 days, compared to September's 95 mm (3.7 in) across just 9 days. Humidity levels remain fairly similar, with September at 83% and July at 80%, indicating that both months can feel quite muggy, but September's slightly lower humidity may provide a more comfortable atmosphere overall. For more detailed insights on July weather, visit North weather in July.

In comparing the weather of September and August, we see some interesting differences. September features a wider temperature range with a minimum of 11°C (52°F) and a maximum of 37°C (99°F), while August is consistently warmer with a minimum of 16°C (62°F) and a maximum of 36°C (98°F). The average temperatures in September are slightly lower at 25°C (78°F) compared to August's 27°C (81°F). Precipitation also varies, with September receiving 95 mm (3.7 in) over 9 days, significantly less than August's 148 mm (5.8 in) across 18 days. Additionally, September maintains a higher humidity level at 83%, compared to August's 81%. For a closer look at the specifics, you can check out North weather in August.

September typically experiences warmer temperatures, with an average of 25°C (78°F) and highs reaching up to 37°C (99°F). In contrast, October sees a significant drop in minimum temperatures, averaging only 1°C (35°F), while the overall average cools to 21°C (70°F). Precipitation also declines slightly in October, with 69 mm (2.7 in) over 7 days compared to September's 95 mm (3.7 in) over 9 days. Additionally, October features lower humidity levels at 78%, making the cooler temperatures feel even more refreshing. For more insights on October weather, visit North weather in October.

September and November present quite a contrast in weather patterns. September features a warmer climate, with average temperatures around 25°C (78°F) and highs peaking at 37°C (99°F), while November cools significantly, showcasing an average of 13°C (56°F) and minimum temperatures dipping to -3°C (27°F). Despite a higher average temperature, September experiences more rainfall, with 95 mm (3.7 in) over 9 days, compared to November's 62 mm (2.4 in) over 7 days. The humidity remains relatively consistent, sitting at 83% in September and slightly lower at 85% in November. For more detailed insights into November weather, you can check North weather in November.

In September, the weather is characterized by warm temperatures, with a minimum of 11°C (52°F) and an average of 25°C (78°F), reaching up to a maximum of 37°C (99°F). This month experiences significant rainfall, totaling 95 mm (3.7 in) over about 9 days, accompanied by high humidity levels at 83%.

In contrast, December brings much cooler conditions, with temperatures dipping as low as -6°C (22°F) at night and averaging around 11°C (52°F) during the day. Although the maximum temperature can reach 27°C (81°F), the month is notably wetter, with precipitation of 128 mm (5.1 in) spread over 10 days and slightly higher humidity at 87%. For more insights into the December weather trends, you can visit North weather in December.

Compare North's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in North

As September unfolds in North, it marks a notable transition from the sweltering heat of summer to a more temperate climate. The temperatures range from pleasantly mild evenings to warm days, providing a refreshing break compared to the peak summer swelters. With humidity levels reaching 83%, the air feels humid, especially during brief afternoon showers that result in around 95 mm of precipitation over nine days. This month sets the stage for autumn, where the mix of sun and rain nurtures the environment, making it markedly different from the drier, hotter months preceding it. For further insights on weather patterns, visit North Climate.