Last updated: February 24, 2025
In September, Bloomington, United States experiences a diverse climate characterized by a maximum temperature soaring to 33°C (91°F), while the average temperature hovers around a comfortable 18°C (65°F). As the month transitions into autumn, temperatures can dip to a minimum of 2°C (35°F). This time of year also sees significant precipitation, with 120 mm (4.7 in) of rain spread across about 9 days, contributing to a relative humidity level of 81%. The blend of warm days and cooler nights, coupled with periodic rainfall, makes September a captivating month in Bloomington.
In September, Bloomington transitions from the heat of summer to the crispness of autumn, showcasing a delightful range of temperatures. With a minimum temperature of 2°C (35°F) and a maximum reaching 33°C (91°F), the month offers a comfortable average of 18°C (65°F). This period marks a significant drop from the sweltering days of July and August, when temperatures often peaked at 35°C (94°F). As days grow shorter and the air becomes cooler, residents can enjoy the refreshing change while preparing for the cooler months ahead. Overall, September in Bloomington provides a beautiful and invigorating blend of warmth and the early whispers of fall, making it a lovely time for outdoor activities.
In September, Bloomington experiences a notable shift in its precipitation patterns, with 120 mm (4.7 in) of rainfall over an average of 9 days. This marks a dip from the robust totals of the summer months, such as August's 134 mm (5.3 in), yet remains substantial enough to nurture the lush landscapes as the season transitions into fall. September's weather is a precursor to the drier months ahead, with October typically seeing a decrease in rainfall to 92 mm (3.6 in). This trend highlights the gradual shift from the late summer warmth and moisture towards cooler and crisper autumn days, creating a dynamic interplay between wet and dry periods as the year winds down.
In September, humidity levels in Bloomington, United States, settle at 81%, mirroring the consistency seen in the preceding summer months of July and August. Throughout the year, humidity starts high during the winter, peaking at 90% in February, and gradually declines towards the warmer months. As spring transitions to summer, the humidity begins to ease, only to stabilize again in early fall. This trend illustrates a dynamic seasonal shift, where gripping humidity gives way to a slightly drier atmosphere, creating a comfortable environment as autumn approaches. The upcoming months see a return to increased moisture, with November noticeably climbing to 88%, hinting at the cyclical nature of Bloomington’s climate.
As summer fades and September arrives in Bloomington, the UV Index reflects a significant shift, dropping to a high level of 7. This change highlights an easing in sun intensity compared to the peak months of June to August, where UV levels reached their maximum at 10. Sun exposure remains critical, with a burn time of 25 minutes, reminding us to take precautions during outdoor activities. The trend of decreasing UV Index levels will continue into the fall, transitioning to a moderate index of 5 by October. This gradual decline signifies a return to more manageable sun exposure, yet it's still essential to be mindful of skin protection. For more detailed information, check out Bloomington UV Index.
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As summer wanes, September in Bloomington brings a warm transition, with an impressive 254 hours of sunshine, making it one of the sunniest months of the year. Following a peak in July with 362 hours of bright skies, the hours slightly dip, yet still remain vibrant, reminiscent of the summer’s glow. This month serves as a splendid farewell to the long days, trailing just behind the sun-drenched heights of May and June. The consistent sunshine in September contributes to a lingering warmth, inviting both residents and visitors to enjoy the beautiful outdoors before autumn settles in. With daylight hours steadily decreasing into October, September emerges as a celebration of luminous days, capturing the essence of late summer's charm.
As summer transitions into fall, Bloomington experiences a notable increase in sunny days, with September boasting a remarkable 63% chance of sun. This uptick follows the sunny trends established in the previous summer months, August at 62% and July at 57%. The consistent rise in sunshine from earlier in the year highlights a shift in weather patterns; after the gloom of winter and the variability of spring, residents can finally bask in the warm golden rays of September sun. The favorable forecast invites outdoor activities and gatherings, making it a perfect month to enjoy the lingering warmth before autumn fully sets in.
As summer fades into autumn, September in Bloomington experiences a gradual transition in daylight duration, with the sun gracing the skies for 12 hours each day. This marks a gentle decline from the lengthy, sun-soaked days of summer, where July and June basked in 15 hours of daylight. The daylight hours begin to wane as the month progresses, setting the stage for the shorter days of October with its 10 hours of light. This trend reveals a rhythmic ebb and flow of daylight that characterizes the changing seasons, inviting residents to savor the lingering warmth of early fall before the crisp embrace of winter descends.
As September rolls into Bloomington, the average wind speed hovers around 3.4 m/s (8 mph), a refreshing change from the summer's calm breezes. Interestingly, this month mirrors May's light winds, suggesting a lovely transition into fall. While the earlier months of the year display slightly higher winds, particularly in November with its 3.9 m/s (9 mph) gusts, late summer and early fall maintain a gentle flow. The overall trend reveals a mellowing down as the year progresses, with cool autumn winds promising to stir the vibrant foliage while balancing the warmth of lingering summer days.
The weather in Bloomington 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 Bloomington and find detailed weather information for every month.
September and January present stark contrasts in weather conditions. In September, temperatures range from a mild 2°C (35°F) at night to a warm 33°C (91°F) during the day, accompanied by an average of 120 mm (4.7 in) of precipitation over about 9 days and a humidity level of 81%. In comparison, January is characterized by significantly colder temperatures, with a chilling minimum of -34°C (-28°F) and an average temperature of -8°C (17°F), reaching a maximum of only 7°C (45°F). Precipitation during this month is much lower, totaling around 30 mm (1.2 in) and occurring over just 5 days, while the humidity remains relatively high at 87%. For more details, check Bloomington weather in January.
When comparing September and February weather, the differences are striking. September boasts a temperature range from a chilly 2°C (35°F) to a warm 33°C (91°F), averaging around 18°C (65°F), while February sees much harsher conditions with temperatures plummeting to a minimum of -35°C (-31°F) and averaging around -8°C (17°F). Precipitation is more abundant in September at 120 mm (4.7 in) over 9 days, compared to February's lower total of 36 mm (1.4 in) spread over just 6 days. Additionally, humidity levels are similar, with September at 81% and February slightly higher at 90%. For more detailed insights on February weather, check out Bloomington weather in February.
September and March present contrasting weather experiences. In September, temperatures range from a cool 2°C (35°F) at night to a warm 33°C (91°F) during the day, with an average temperature of 18°C (65°F). The month sees about 120 mm (4.7 in) of precipitation over approximately 9 days, and humidity levels remain high at 81%. In contrast, March features much colder conditions, with minimum temperatures plummeting to -25°C (-13°F) and a maximum of 22°C (73°F), averaging around 1°C (34°F). Precipitation is lighter at 60 mm (2.4 in) over 7 days, while humidity rises slightly to 85%. For further details, visit Bloomington weather in March.
When comparing the weather in September and April, notable differences arise in both temperature and precipitation. September experiences a wider temperature range with minimums around 2°C (35°F) and maximums reaching up to 33°C (91°F), while April has a colder minimum of -13°C (8°F) and a milder maximum of 29°C (84°F). Additionally, September sees an average temperature of 18°C (65°F) compared to April's average of 6°C (44°F). In terms of precipitation, September is wetter with 120 mm (4.7 in) over 9 days, while April has slightly less at 84 mm (3.3 in), also over 9 days. Both months have high humidity levels, but September's is slightly lower at 81% compared to April's 84%. For more detailed insights, check out Bloomington weather in April.
When comparing the weather in September and May, it is clear that both months experience a range of temperatures and precipitation. September features a minimum temperature of 2°C (35°F) and an average of 18°C (65°F), with maximums reaching up to 33°C (91°F). In contrast, May has a slightly lower average temperature of 15°C (59°F), with minimums around -1°C (31°F) and highs that can soar up to 36°C (98°F). Precipitation is also notable in both months, with September receiving 120 mm (4.7 in) over 9 days, while May sees a bit more rainfall at 137 mm (5.4 in) across 12 days. Interestingly, September has a higher humidity level of 81%, compared to 78% in May. For more detailed information about May weather specifically, you can check Bloomington weather in May.
When comparing September to June weather, we see some notable differences. June generally offers warmer temperatures, with minimums around 7°C (46°F) and maximums reaching up to 35°C (96°F), while September experiences a broader temperature range, dipping to a minimum of 2°C (35°F) and peaking at 33°C (91°F). The average temperature in June is also higher at 22°C (72°F) compared to September’s 18°C (65°F). Additionally, June receives slightly less precipitation at 97 mm (3.8 in) over 11 days, whereas September has more rainfall at 120 mm (4.7 in) over just 9 days. Humidity levels are quite similar, with June at 80% and September at 81%. For those interested in more detailed weather information, you can explore Bloomington weather in June.
When comparing the weather in September and July, notable differences in temperature and precipitation emerge. September experiences a wider temperature range, with minimums dipping to 2°C (35°F) and maximums reaching up to 33°C (91°F), averaging around 18°C (65°F). In contrast, July boasts milder lows at 13°C (56°F) and generally warmer temperatures, peaking at 35°C (94°F) and averaging 24°C (75°F). Precipitation is slightly higher in September, totaling 120 mm (4.7 in) over 9 days, compared to July's 106 mm (4.2 in) over 10 days. Both months share a consistent humidity level of 81%. For more details on July weather, visit Bloomington weather in July.
In September, the weather experiences a noticeable shift compared to August. The minimum temperature drops significantly to 2°C (35°F), while the average temperature falls to 18°C (65°F), which is a decrease from August’s more temperate minimum of 11°C (51°F) and average of 22°C (71°F). The maximum temperatures remain quite similar, with September reaching up to 33°C (91°F) compared to August's 32°C (90°F). Precipitation levels in September are slightly lower at 120 mm (4.7 in) over 9 days, compared to August’s 134 mm (5.3 in) over 11 days. Despite the differences in temperature and precipitation, humidity remains constant at 81% for both months. For a more in-depth analysis of August weather conditions, you can check out Bloomington weather in August.
September weather is characterized by a warm average temperature of 18°C (65°F) and daytime highs reaching up to 33°C (91°F), making it a generally pleasant month. However, it also brings significant humidity at 81% and about 120 mm (4.7 in) of precipitation over 9 days. In contrast, October sees a substantial drop in average temperature to 9°C (49°F) with cooler nights that can plunge to -9°C (16°F). While the maximum temperature remains comfortable at 29°C (85°F), October experiences slightly more precipitation over 11 days, totaling 92 mm (3.6 in) and a marginally higher humidity level at 84%. For more detailed insights, you can check Bloomington weather in October.
September weather is characterized by a wider temperature range, with minimums around 2°C (35°F) and maximums reaching up to 33°C (91°F), creating warm afternoons and cool nights. In contrast, November brings much colder temperatures, with lows dipping to -16°C (4°F) and a high of only 24°C (75°F), indicating a shift towards winter. Additionally, September experiences more precipitation, totaling 120 mm (4.7 in) over about 9 days, compared to November's 36 mm (1.4 in) over 7 days, though the humidity remains high in both months at 81% in September and 88% in November. For more detailed information on November weather, you can view Bloomington weather in November.
The weather in September is characterized by a warm average temperature of 18°C (65°F), with daily highs reaching up to 33°C (91°F), while winter descends in December, bringing much colder conditions with an average temperature of -5°C (24°F) and maximums of just 14°C (57°F). September also experiences significant rainfall, totaling 120 mm (4.7 in) over about nine days, whereas December sees much less precipitation at 49 mm (1.9 in) across seven days. Humidity levels remain relatively high in both months, at 81% in September and slightly higher at 84% in December. For more details on the winter weather, you can check Bloomington weather in December.
As September unfolds in Bloomington, the weather showcases a remarkable transition from the sweltering heat of summer to the refreshing embrace of autumn. With temperatures comfortably averaging 18°C (65°F), the month offers a delightful reprieve from the extremes, punctuated by brief spells of warmth that can still push to a maximum of 33°C (91°F). Notably, September experiences a higher humidity level, averaging around 81%, together with approximately 120 mm (4.7 in) of rainfall spread over 9 days, contributing to the lush landscapes that characterize this time of year. This blend of warmth and moisture marks September as a unique month, bridging the gap between the sun-drenched days of summer and the cool, crisp mornings of fall. To learn more about the weather patterns throughout the year, visit Bloomington Climate.