Last updated: February 24, 2025
In September, Rapid City experiences a notable range of temperatures, with a striking maximum reaching 37°C (100°F), a comfortable average of 16°C (62°F), and a chilly minimum dipping to -4°C (26°F). This month typically sees 43 mm (1.7 in) of rainfall over approximately 7 days, contributing to a humidity level of 76%. Such conditions create a diverse climate, perfect for outdoor activities while also reminding residents of the seasonal transitions characteristic of the region.
In September, Rapid City experiences a notable transition, with temperatures reflecting the shift from the peak of summer to the onset of autumn. The minimum temperature settles around a brisk -4°C (26°F), while the average climbs to a comfortable 16°C (62°F), allowing for pleasant outdoor activities. The maximum reaches up to 37°C (100°F) on warmer days, reminiscent of summer. As the month progresses, the cooler nights begin to foreshadow the approaching winter, contrasting sharply with the sweltering highs often felt in the prior months. This blend of warmth and crispness makes September a unique time in Rapid City's climate, enticing both residents and visitors to relish the outdoors before the chill sets in.
In September, Rapid City experiences a transition in its precipitation patterns as the summer warmth begins to wane. With an average of 43 mm (1.7 in) of rainfall over 7 days, September marks a notable decrease compared to the wetter months of May and July. This month serves as a bridge between the lush, rain-filled summer and the emerging dryness of autumn, often characterized by a mix of crisp days and lingering rainfall. The reduced precipitation reflects a broader trend, as Rapid City's weather shifts from the peak summer highs to the drier, chillier months ahead, with October following closely with a slight uptick to 52 mm. Thus, September not only brings a refreshing change in temperature but also signals the gradual tapering of the region's wetter season.
In September, Rapid City experiences a notable shift in humidity, averaging around 76%, which marks a decrease from the peak levels of the summer months. As the heat of July and August, both at 85%, begins to wane, September provides a more comfortable and refreshing atmosphere. This transition hints at the arrival of autumn, as humidity levels dip yet remain elevated compared to the earlier months of the year like March and April, which hovered around 64% and 66%, respectively. Overall, while September's humidity is relatively high, it signifies the gradual shift towards drier conditions that will continue into the fall.
In September, Rapid City experiences a UV Index of 8, categorized as very high, which signifies a continued trend of elevated sun exposure as summer wanes. With an estimated burn time of just 15 minutes, it's crucial for residents and visitors to stay vigilant against harmful UV rays, especially as they transition from the extreme levels seen in June and July to this still significant index. As autumn approaches, this month serves as a reminder to protect your skin while outdoors. For more detailed information, check out the Rapid City UV Index.
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In Rapid City, September shines with a captivating 288 hours of sunshine, making it a delightful transition from the sun-drenched summer months. As the days begin to cool, this month showcases a remarkable consistency in sunlight, exceeding the earlier months of the year, particularly March through August. It's interesting to note that September's sunlight hours still surpass those of fall and winter, creating a vibrant backdrop for outdoor activities amidst the changing foliage. With a gradual decline seen as October approaches, the city’s charming blend of crisp air and lingering warmth invites residents and visitors alike to savor the beauty of an Indian summer before the shorter days set in.
As September arrives in Rapid City, residents and visitors alike can anticipate a sunny outlook, with a 67% chance of sunshine gracing the skies. Following the peak summer months of July and August, which boast 63% and 72% sunshine, respectively, September continues this trend of bright days while ushering in the beauty of early autumn. The likelihood of sunny weather notably stabilizes, making it a great time for outdoor activities and exploration. As the summer heat tapers off, this month strikes a perfect balance, promising plenty of opportunities to enjoy the natural splendor of the Black Hills under clear skies.
As summer recedes, September in Rapid City witnesses a gradual transition in daylight duration, capturing the essence of early autumn. With an average of 12 hours of daylight, this month marks a gentle decline from the sunniest peak of 15 hours seen in June and July. The gradual shortening of days echoes the changing seasons, as daylight begins to wane ahead of the chillier months. Following the vibrant blooms of summer, September hints at a cozy shift, offering an opportunity to enjoy the last warm rays before the daylight dips further to 10 hours in October. This fluctuation not only reflects nature's rhythm but also invites residents to embrace the beauty of changing light and landscape.
As September arrives in Rapid City, the winds begin to pick up slightly, with an average speed of 3.4 m/s (8 mph), aligning with the breezier spring months. This marks a seasonal shift, as the summer months witnessed calmer winds, averaging around 3.2 m/s (7 mph). Interestingly, late summer's tranquility gives way to a bit more movement in the air, hinting at the change of seasons. The wind speeds in September serve as a prelude to the more consistent breezes of autumn, with October and November nudging back up to 3.9 m/s (9 mph). This gradual increase not only enriches the atmosphere, but also signals nature's transition, blending the lingering warmth of summer with the crispness of fall.
The weather in Rapid City 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 Rapid City and find detailed weather information for every month.
When comparing the weather in September and January, one can see a stark contrast. September experiences mild temperatures with a minimum of -4°C (26°F) and an average of 16°C (62°F), peaking at a scorching 37°C (100°F). This month also sees a higher precipitation level of 43 mm (1.7 in) over 7 days, while humidity averages at 76%. In contrast, January is much colder, with temperatures plummeting to a minimum of -26°C (-14°F) and averaging -3°C (27°F), with a maximum of only 16°C (61°F). This winter month has significantly lower precipitation at 14 mm (0.5 in) over just 4 days and a slightly lower humidity of 73%. The differences highlight the transition from the warmth of early autumn to the chill of mid-winter. For a deeper look into typical January conditions, you can visit Rapid City weather in January.
September and February present stark contrasts in weather patterns. In September, temperatures range from a chilly -4°C (26°F) at night to a warm 37°C (100°F) during the day, with an average around 16°C (62°F). The month typically receives 43 mm (1.7 in) of precipitation over 7 days, accompanied by a humidity level of 76%. In contrast, February experiences much colder conditions, with temperatures plummeting to a minimum of -29°C (-19°F) and reaching a maximum of 21°C (69°F), averaging -6°C (22°F). Precipitation is lower at 27 mm (1.1 in) over 7 days, and humidity rises slightly to 78%. For more details about weather conditions in February, check out Rapid City weather in February.
In comparing the weather patterns of September and March, notable differences in temperature and conditions emerge. September features a milder climate with an average temperature of 16°C (62°F) and maximum highs reaching up to 37°C (100°F), while March experiences much colder temperatures, averaging only 2°C (36°F) and dipping as low as -26°C (-14°F). Precipitation levels are quite similar, with September receiving 43 mm (1.7 in) over about 7 days and March slightly edging out with 44 mm (1.7 in) across 8 days. In terms of humidity, September is wetter at 76%, compared to March's lower level of 64%. For a closer look at the specifics of March weather, visit Rapid City weather in March.
When comparing the weather in September and April, notable differences emerge. September typically enjoys a wider temperature range, with lows around -4°C (26°F) and highs reaching up to 37°C (100°F), resulting in an average temperature of 16°C (62°F). This month sees a moderate amount of precipitation, averaging 43 mm (1.7 in) over about seven days, accompanied by relatively high humidity at 76%.
In contrast, April experiences cooler conditions, with minimum temperatures dipping to -16°C (3°F) and maximums capping at 25°C (77°F), leading to a much lower average of 5°C (41°F). While April receives more precipitation at 73 mm (2.9 in) spread over approximately 11 days, the humidity is slightly lower at 66%. For more detailed information about April weather patterns, you can visit Rapid City weather in April.
In comparing the weather of September and May, September boasts a wider temperature range, with minimums dipping to -4°C (26°F) and maximums soaring up to 37°C (100°F), leading to an average of 16°C (62°F). In contrast, May exhibits cooler conditions overall, with a maximum temperature of 30°C (86°F) and an average of 11°C (53°F). September tends to be drier, receiving about 43 mm (1.7 in) of precipitation over 7 days, whereas May experiences more rainfall, totaling 112 mm (4.4 in) across 17 days of precipitation. Humidity levels remain relatively similar, at 76% in September and 74% in May, creating a moderately humid climate throughout both months. For more detailed insights, check Rapid City weather in May.
September's weather offers a wider temperature range compared to June, with minimums dropping to -4°C (26°F) and maximums peaking at 37°C (100°F). The average temperature in September is slightly lower at 16°C (62°F), while June enjoys an average of 19°C (67°F). Additionally, June experiences more precipitation, with 72 mm (2.8 in) over 13 days, compared to September's 43 mm (1.7 in) over 7 days. Humidity levels are also higher in June at 84%, compared to September's 76%. For more detailed information, you can check Rapid City weather in June.
When comparing the weather in September and July, one can observe distinct variations. September experiences a broader temperature range, with minimums dipping to -4°C (26°F) and maximums reaching up to 37°C (100°F), while the average temperature hovers around 16°C (62°F). In contrast, July tends to be milder, starting at a minimum of 9°C (49°F) and peaking at 38°C (100°F), with an average of 22°C (72°F). Additionally, July is marked by significantly higher precipitation, accumulating 96 mm (3.8 in) over 16 days, compared to September’s 43 mm (1.7 in) over just 7 days. Humidity levels in July are also higher at 85%, compared to September's 76%. For a detailed look at July weather, you can check Rapid City weather in July.
In September, temperatures in Rapid City exhibit a wider range, with a minimum of -4°C (26°F) and a maximum reaching 37°C (100°F), while the average temperature drops to 16°C (62°F). This contrasts with August, where the temperatures are generally milder, with a minimum of 7°C (44°F) and an average of 20°C (69°F), peaking at the same maximum of 37°C (98°F).
Precipitation also differs between the two months; September receives 43 mm (1.7 in) over 7 days, whereas August sees more rain at 57 mm (2.2 in) across 12 days. August's higher humidity of 85% compared to September's 76% further emphasizes the transition from summer to fall. For more details on August weather patterns, you can check Rapid City weather in August.
September and October present notable differences in weather patterns. September experiences a wider temperature range with minimums around -4°C (26°F) and maximums climbing up to 37°C (100°F), resulting in an average temperature of 16°C (62°F). In contrast, October sees much cooler temperatures, with minimums plummeting to -18°C (-1°F) and a significantly lower average of 7°C (45°F), though it retains a maximum of 30°C (86°F). Both months have similar levels of precipitation, with September recording 43 mm (1.7 in) over 7 days and October slightly higher at 52 mm (2.0 in) over 8 days. Humidity levels also decrease in October to 71%, compared to September's 76%. For a detailed overview of the weather in October, visit Rapid City weather in October.
September and November present strikingly different weather patterns. In September, temperatures range from a chilly -4°C (26°F) at night to a scorching 37°C (100°F) during the day, with an average of 16°C (62°F). This month typically experiences 43 mm (1.7 in) of rainfall over about 7 days, accompanied by relatively high humidity at 76%. In contrast, November sees significantly colder conditions, with nighttime lows plummeting to -19°C (-2°F) and daytime highs reaching only up to 24°C (75°F), resulting in an average temperature of just 3°C (37°F). Precipitation decreases to 17 mm (0.7 in) over 5 days, and humidity remains slightly lower at 73%. For more details on weather specifics, check out Rapid City weather in November.
In September, the weather is significantly warmer, with temperatures ranging from a chilly -4°C (26°F) at night to a sweltering 37°C (100°F) during the day, averaging around 16°C (62°F). The month experiences about 43 mm (1.7 in) of precipitation over 7 days, coupled with a humidity level of 76%. In contrast, December brings much colder conditions with temperatures dipping as low as -23°C (-10°F) at night and peaking at 21°C (70°F) during the day, resulting in an average temperature of -1°C (30°F). Precipitation decreases slightly to 28 mm (1.1 in) over 6 days, and humidity remains comparable at around 75%. For more specifics on December's weather, you can refer to Rapid City weather in December.
As September unfolds in Rapid City, it marks a distinct transition from the scorching summer months to the cooler embrace of autumn. While you can still expect some warm days, the drastic drop in nighttime temperatures brings a refreshing chill, setting the stage for sweaters and cozy evenings. Humidity levels often peak, adding a soft blanket-like feel to the air, and occasional rain showers can provide a much-needed reprieve from the heat. With an average temperature that balances both warmth and coolness, September offers a unique blend of Indian summer days and crisp fall nights, making it a delightful time to experience the beauty of the Black Hills. For more insights on the ever-changing weather patterns, visit Rapid City Climate.