September Weather in Bethlehem, United States

Last updated: February 24, 2025

September in Bethlehem, United States offers a captivating transition from summer to early autumn. The maximum temperature peaks at a warm 29°C (85°F), while the average settles comfortably at 15°C (58°F), showcasing the month’s delightful variability. However, as the days grow shorter, temperatures can dip to a minimum of -5°C (23°F) during the nights, bringing a refreshing chill. This month also witnesses 69 mm (2.7 in) of precipitation spread across 9 days, contributing to a humidity level of 77% that enhances the lively, crisp atmosphere. Whether enjoying the gentle warmth or refreshing breezes, September in Bethlehem is a canvas of changing seasons, perfect for outdoor adventures and cozy moments alike.

September Temperature in Bethlehem

As summer transitions to autumn, September in Bethlehem showcases a noticeable shift in temperatures that embody the essence of early fall. With a minimum temperature of -5°C (23°F), the evenings begin to chill, while the average temperature rises to a comfortable 15°C (58°F), providing a pleasant backdrop for outdoor activities. Daytime highs can reach a pleasant 29°C (85°F), hinting at the residual warmth of summer. This blend of cooler mornings and mild afternoons signifies a gentle bridge towards the crisper days of October, marking September as a month of delightful contrast and gradual change in Bethlehem's climate.

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

The chart illustrates September temperature patterns in Bethlehem, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec172027405362676558473222
Data source: Temperature data for Bethlehem 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 Bethlehem

In September, Bethlehem experiences a notable drop in precipitation, with only 69 mm (2.7 in) of rain falling over 9 days, which marks the end of the summer season. This decrease in rainfall continues the trend observed in August, where 91 mm (3.6 in) was recorded, and significantly contrasts with the wetter months preceding it, like April, which saw 125 mm (4.9 in). As the months transition into autumn, the overall trend indicates a gradual decrease in precipitation, culminating in an increase again by October, when rain levels rise to 140 mm (5.5 in). This ebb and flow of rainfall not only shapes the local landscape but also heralds the arrival of vibrant fall foliage in the region.

September Precipitation Trends in Bethlehem

The chart displays monthly precipitation patterns in Bethlehem, 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.
JanFebMarAprMayJunJulAugSepOctNovDec8685771251041091199169140116100
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Bethlehem

In September, Bethlehem experiences a moderate humidity level of 77%, marking a slight uptick from the drier months of summer. This increase indicates a gradual transition as the city prepares for the more humid conditions typical of autumn. Notably, humidity begins to rise again after the summer dip, suggesting that while the heat may recede, the air retains a notable moisture content. As the year progresses, humidity in Bethlehem fluctuates, peaking during the winter with levels around 91% in January. Overall, September stands out as a point of balance, reflecting the shifting seasons and setting the stage for the more humid months ahead.

September Average Humidity in Bethlehem

This chart illustrates the average monthly humidity levels in Bethlehem, 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.
JanFebMarAprMayJunJulAugSepOctNovDec91%89%85%84%78%72%75%74%77%85%86%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Bethlehem

As summer transitions into fall, the UV Index in Bethlehem reflects a gradual decline in sun intensity. In September, the UV Index sits at 7, classified as high, which means residents should still take precautions when outdoors, with a burn time of approximately 25 minutes. This trend follows a peak in June with a UV Index of 10, and while September's index is notably lower, it's essential to remain vigilant against UV exposure, particularly as the days begin to shorten. With the onset of October, the UV Index further dips to 5, indicating a shifting pattern toward more moderate sunlight exposure. For more details on the UV Index throughout the year, you can visit Bethlehem UV Index.

Maximum UV Index Levels in Bethlehem for September

The chart shows the monthly maximum UV Index (UVI) for Bethlehem 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.
JanFebMarAprMayJunJulAugSepOctNovDec2468910997532
Data source: Bethlehem 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 Bethlehem

As the summer heat begins to wane, September in Bethlehem, United States, offers a delightful blend of warmth and sun, delivering an impressive 275 hours of sunshine. This marks a graceful transition from the sun-soaked peaks of July and August, which basked in 318 and 322 hours respectively. Nature slowly begins to prepare for autumn, while residents still enjoy those golden rays that linger through the early days of fall. The sunshine of September perfectly encapsulates the essence of change—providing a vibrant backdrop for outdoor activities before cooler days set in, reflecting a trend of abundant light as the season shifts but slowly yielding to the shorter daylight hours of October.

Monthly Sunshine Duration in Bethlehem: September Highlighted

The September sunshine duration represents the total number of hours Bethlehem 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.
JanFebMarAprMayJunJulAugSepOctNovDec111h154h226h206h250h308h318h322h275h183h151h136h
Data source: Bethlehem September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Bethlehem During September

In Bethlehem, September brings a 36% chance of sunny weather, a noticeable uptick compared to the summer months of July and August, which reflect the lowest chances of sunlight at 22% and 31%, respectively. This increase suggests that as summer transitions to autumn, there's a greater likelihood of clear skies and pleasant weather that many locals and visitors alike can appreciate. Interestingly, September's sunny potential is rivaled only by the winter month of November, which boasts a 45% likelihood, indicating that even as the days start to shorten, the sun can still make a significant appearance. Overall, September's weather presents a delightful blend of warmth and sunshine, making it an appealing time to enjoy outdoor activities in this charming U.S. town.

Percentage of Sunny Days in September in Bethlehem

The chart illustrates the percentage of sunny days in Bethlehem 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 Bethlehem experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec28%27%46%30%33%37%22%31%36%29%45%26%
Data source: Bethlehem September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Bethlehem in September

As summer gracefully transitions into autumn, September in Bethlehem, United States, showcases a shift in daylight that gently mirrors the changing seasons. With 12 hours of daylight, this month marks a gradual decline from the peak of 15 hours in June and July, reflecting the onset of shorter days as the light begins to wane. The increase in daylight minutes from January's 9 hours to September's moderate levels highlights a vibrant progression through spring and summer, peaking in May. As we move from September into October, the daylight continues to decrease, paving the way for the cozy ambiance of fall and winter. This cyclical dance of daylight encapsulates the rhythmic nature of the seasons, inviting residents to appreciate the beauty and warmth of each fleeting moment.

Average Daylight Hours in Bethlehem for September

The chart illustrates the variation in daylight duration in Bethlehem throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 17m10h 28m11h 57m13h 29m14h 47m15h 26m15h 5m13h 55m12h 27m10h 55m9h 35m8h 54m
Data source: Bethlehem daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Bethlehem

As September unfolds in Bethlehem, the wind picks up slightly from the summer lull, averaging 2.5 m/s (6 mph). This gentle breeze marks a subtle transition from the quieter, slower-moving air of the warmer months. Throughout the year, the wind speeds have shown a seasonal rhythm: generally lighter in the depths of summer, reaching their peak in spring, then tapering off again as autumn approaches. Interestingly, September stands as a middle ground, maintaining a balance between the summer’s calm and the briskness of autumn's arrival. It's a refreshing reminder of nature's ebb and flow, with the wind inviting residents to step outside and embrace the changing season.

Average September Wind Speed in Bethlehem

The chart displays monthly wind speed patterns in Bethlehem, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.32.63.32.82.42.72.01.92.5 m/s2.22.52.8
Data source: Bethlehem September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Bethlehem Compares to Other Months

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

In September, temperatures in Bethlehem can vary significantly, with a minimum of -5°C (23°F) and a warm average of 15°C (58°F), reaching highs of 29°C (85°F). This month sees about 69 mm (2.7 in) of precipitation over approximately 9 days, accompanied by a humidity level of 77%. In contrast, January brings much colder weather, with temperatures dipping to a chilling minimum of -31°C (-23°F) and averaging -8°C (17°F), peaking at only 12°C (54°F). Precipitation increases slightly to 86 mm (3.4 in) spread over around 12 days, and humidity rises to 91%. For more details, check out Bethlehem weather in January.

In comparing September and February weather, it's clear that these months showcase stark contrasts. September experiences a temperature range from a chilly -5°C (23°F) at its lowest to a warm maximum of 29°C (85°F), with an average of 15°C (58°F). The month sees less precipitation, totaling 69 mm (2.7 in) over 9 days, and a humidity level of 77%. Meanwhile, February is much colder, with temperatures ranging from a frigid -27°C (-16°F) to a maximum of 16°C (62°F), and an average temperature of -7°C (20°F). This month has higher precipitation at 85 mm (3.4 in) over 13 days and increased humidity at 89%. For a more detailed look at February weather in Bethlehem, check out Bethlehem weather in February.

In comparing the weather of September and March, one can observe notable contrasts. September typically experiences milder temperatures, ranging from a minimum of -5°C (23°F) to a maximum of 29°C (85°F), with an average of 15°C (58°F). The month sees a moderate level of precipitation, with around 69 mm (2.7 in) falling over approximately 9 days, and humidity levels at 77%. In contrast, March is much colder, with temperatures ranging from a minimum of -22°C (-8°F) to a maximum of 18°C (65°F), averaging -3°C (27°F). This month records slightly more precipitation at 77 mm (3.0 in) over 11 days and higher humidity at 85%. For a more detailed look at March weather, you can check out Bethlehem weather in March.

In comparing the weather between September and April, we notice distinct differences in temperature and precipitation. September tends to be warmer, with average temperatures ranging from a chilly -5°C (23°F) at night to a pleasant 29°C (85°F) during the day, while April experiences cooler temperatures, with a minimum of -12°C (10°F) and a maximum of 24°C (76°F). Precipitation is more frequent in April, with 125 mm (4.9 in) over 16 days, compared to 69 mm (2.7 in) over 9 days in September. Humidity is also higher in April, averaging 84% compared to September's 77%. For a more detailed look at what to expect, check out Bethlehem weather in April.

When comparing the weather in September and May, several key differences emerge. September enjoys a range of temperatures, with a minimum of -5°C (23°F) and a maximum of 29°C (85°F), leading to an average of 15°C (58°F). The month experiences lighter precipitation, totaling 69 mm (2.7 in) over about 9 days, and has a relatively high humidity of 77%. In contrast, May sees slightly warmer temperatures, with a minimum of -3°C (27°F) and a peak of 31°C (87°F), averaging around 12°C (53°F). However, it experiences more substantial rainfall, accumulating 104 mm (4.1 in) across approximately 13 days, and a humidity level that is slightly higher at 78%. For more insight into the weather specifics for May, you can check Bethlehem weather in May.

When comparing the weather in September and June, notable differences emerge. September experiences a broader temperature range, with minimums dipping to -5°C (23°F) and maximums reaching 29°C (85°F), averaging about 15°C (58°F). In contrast, June tends to be slightly warmer overall, with minimum temperatures around -1°C (31°F) and maximums peaking at 31°C (88°F); it has an average temperature of 17°C (62°F). Additionally, June has more precipitation, with 109 mm (4.3 in) over 12 days compared to September's 69 mm (2.7 in) across 9 days, although September's humidity is slightly higher at 77% versus June's 72%. For a more detailed look at June's weather, you can check Bethlehem weather in June.

When comparing the weather in September and July, a notable difference is evident in temperature and precipitation levels. September experiences a broader temperature range, with minimums dropping to -5°C (23°F) and maximums reaching up to 29°C (85°F), whereas July maintains a milder minimum of 7°C (44°F) and a higher maximum of 33°C (91°F). In addition, July tends to be wetter, with 119 mm (4.7 in) of precipitation over 14 days, compared to September’s 69 mm (2.7 in) over 9 days. Humidity levels are fairly similar, with September at 77% and July at 75%. For more details on the weather patterns, you can check Bethlehem weather in July.

In comparing the weather between September and August, September generally experiences cooler temperatures, with a minimum of -5°C (23°F) compared to August's higher minimum of 4°C (40°F). The average temperature in September is around 15°C (58°F), which is notably lower than August's average of 18°C (66°F). Additionally, the maximum temperatures in September reach up to 29°C (85°F), while August sees a higher maximum of 32°C (89°F). August also has slightly more precipitation at 91 mm (3.6 in) over 13 days, compared to September's 69 mm (2.7 in) over 9 days. Humidity levels are fairly close, with September at 77% and August at 74%. For more detailed information, you can check Bethlehem weather in August.

In comparing the weather between September and October, we see a notable shift in temperature and precipitation. September features a minimum temperature of -5°C (23°F) and an average of 15°C (58°F), with highs reaching up to 29°C (85°F). It experiences about 69 mm (2.7 in) of precipitation over approximately 9 days, alongside a humidity level of 77%. In contrast, October brings cooler temperatures with a minimum of -7°C (20°F), an average of 8°C (47°F), and a maximum of 24°C (76°F). This month also sees a significant increase in precipitation, totaling 140 mm (5.5 in) over 14 days, while humidity rises slightly to 85%. For more details, you can check out Bethlehem weather in October.

In September, temperatures in Bethlehem range from a chilly minimum of -5°C (23°F) to a comfortable maximum of 29°C (85°F), with an average of 15°C (58°F). This month experiences less precipitation, totaling 69 mm (2.7 in) over about 9 days, while humidity averages around 77%. In contrast, November brings much cooler temperatures, with a minimum of -21°C (-5°F) and an average of 0°C (32°F), peaking at 21°C (71°F). The month is wetter, receiving 116 mm (4.6 in) of precipitation over 15 days, alongside higher humidity levels at 86%. For more details, check out Bethlehem weather in November.

In September, temperatures range from a chilly -5°C (23°F) at night to a warm 29°C (85°F) during the day, with an average of 15°C (58°F). The month sees a total precipitation of 69 mm (2.7 in) over about 9 days, accompanied by a humidity of around 77%. In contrast, December brings much colder conditions, with temperatures plunging to as low as -30°C (-21°F) and rarely exceeding 13°C (56°F), leading to an average of -6°C (22°F). This month experiences higher precipitation at 100 mm (3.9 in) spread over 15 days, and humidity increases to 85%. For those interested in more detailed information, you can visit Bethlehem weather in December.

Compare Bethlehem's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Bethlehem

As September rolls into Bethlehem, the weather showcases a unique transition, marked by a significant drop in temperatures compared to the scorching summer months. The air becomes noticeably crisper, paving the way for refreshing conditions that many locals and visitors find invigorating. While occasional rain showers contribute to the month’s overall precipitation, the humidity remains high, enveloping the town in a cozy embrace typical of early fall. This blend of cooler temperatures and intermittent rainfall sets September apart, making it an ideal time to explore the stunning landscapes of the region. For further insights into the climate of this charming town, visit Bethlehem Climate.