December Weather in Rapid City, United States

Last updated: February 24, 2025

December in Rapid City, United States, showcases a striking contrast in temperatures, ranging from a maximum of 21°C (70°F) to a minimum of -23°C (-10°F), with an average chilling at -1°C (30°F). During this month, residents can expect 28 mm (1.1 in) of precipitation over 6 days, contributing to the overall humidity of 75%. This blend of frosty air and intermittent moisture creates a chilly yet occasionally mild atmosphere, making December a unique month for both locals and visitors in the heart of the Black Hills.

December Temperature in Rapid City

In December, Rapid City experiences a significant drop in temperatures, signaling the heart of winter. The month typically sees a minimum temperature around -23°C (-10°F), with an average settling at a frigid -1°C (30°F). Despite the chill, daytime highs can reach up to 21°C (70°F), offering a brief reprieve from the cold. Notably, this month's temperatures demonstrate a transition from the harsh extremes of early winter seen in January and February, where lows can dip even lower. The average temperature in December reflects the city's gradual shift towards milder conditions, providing a hint of warmth amid the wintry landscape. Visitors can expect a picturesque winter wonderland, perfect for enjoying seasonal activities against a backdrop of crisp, cool air.

December Weather in Rapid City: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Rapid City, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec272235415266726961443729
Data source: Temperature data for Rapid City 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.

December Precipitation in Rapid City

In December, Rapid City experiences a notable shift in its precipitation patterns, with an average of 28 mm (1.1 in) of rain falling over approximately 6 days. This marks a slight increase from November's 17 mm (0.7 in), providing a hint of moisture as the city transitions into winter. Compared to the wetter months of spring and early summer, where precipitation levels soar, December's rainfall is relatively modest yet essential for replenishing local water sources. Nevertheless, the amount reflects a year-end trend where precipitation generally tapers off, wrapping up a year that saw May's peak of 112 mm (4.4 in). Thus, December serves as a gentle reminder of the cyclical nature of Rapid City's climate, blending the receding warmth of fall with the chill of winter.

December Precipitation Trends in Rapid City

The chart displays monthly precipitation patterns in Rapid City, with values for each month alongside December's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec1427447311272965743521728
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Rapid City

In December, Rapid City, United States, experiences a relative humidity of 75%, which reflects a slight dip from the notably high levels observed in the summer months. This month sees humidity gradually decreasing from the 84% recorded in June and peaks of 85% in both July and August, marking the year's most humid period. As the seasons shift toward winter, humidity begins to stabilize, with December standing close to the averages seen in early fall and late spring. This trend indicates a transition into drier winter conditions, while still maintaining a moderate level of moisture in the air compared to the rest of the year.

December Average Humidity in Rapid City

This chart illustrates the average monthly humidity levels in Rapid City, with December's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how December's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec73%78%64%66%74%84%85%85%76%71%73%75%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Rapid City

In Rapid City, December ushers in cooler temperatures and a significantly lower UV Index, dropping to 2 in the low exposure category, which allows for a comfortable burn time of 45 minutes. This decrease from the brisk autumn months is a notable shift, as the UV Index had peaked at 9 during the intense summer sunshine. Throughout the year, Rapid City's UV levels fluctuate considerably, with the highest indices in June and July, showcasing extreme exposure, while winter months generally maintain a moderate to low risk. As the year draws to a close, it's a perfect moment for residents and visitors to embrace outdoor activities while enjoying the winter sun safely. To learn more about the UV Index throughout the year, visit Rapid City UV Index.

Maximum UV Index Levels in Rapid City for December

The chart shows the monthly maximum UV Index (UVI) for Rapid City in December, 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.
JanFebMarAprMayJunJulAugSepOctNovDec356991111108532
Data source: Rapid City December 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.

December Sunshine in Rapid City

As the year winds down, December in Rapid City brings a charming glimpse of sunshine with 207 hours of sun—a notable figure that reflects the city's robust annual trend of increasing daylight. After the long days of summer, which peak in July with 382 hours, the fall months see a gradual decline, yet December still boasts a respectable amount of sunny hours compared to the previous winter months. This modest drop hints at a lingering brightness amidst the chilly winter days, offering residents a warm respite and a chance to savor the beauty of the season before hitting the quieter months ahead. As we wrap up the year, Rapid City's sunshine serves as a gentle reminder that even in December, light and warmth continue to shine through.

Monthly Sunshine Duration in Rapid City: December Highlighted

The December sunshine duration represents the total number of hours Rapid City experiences direct sunlight during the month of December, excluding cloudy or obstructed periods. This chart compares the sunshine duration of December with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec169h213h260h283h300h376h382h356h288h247h224h207h
Data source: Rapid City December Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Rapid City During December

In December, Rapid City experiences a 46% chance of sunny weather, a figure that aligns with the relatively cloudy conditions typical of late fall. As we analyze the patterns throughout the year, it's interesting to note that the likelihood of sunny days tends to peak during the summer months, with July and August boasting the highest probabilities at 63% and 72% respectively. Conversely, early winter months, including December, reflect a dip in sunshine, similar to the percentages seen in February, which also presents a lower likelihood of clear skies. Overall, while December may not be the sunniest time of year in Rapid City, its weather trends illustrate a seasonal ebb and flow, suggesting a brief respite from bright days before the sunshine returns with greater frequency in spring and summer.

Percentage of Sunny Days in December in Rapid City

The chart illustrates the percentage of sunny days in Rapid City throughout the year, with December 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 Rapid City experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec52%46%56%48%41%67%63%72%67%61%52%46%
Data source: Rapid City December chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Rapid City in December

As winter settles in Rapid City, December sees a notable decline in daylight, with just 8 hours available each day. This marks the year's lowest point, following a gradual decrease from 15 hours in June and July. The transition from the long, sunlit days of summer to the shorter, dimmer days of winter highlights a clear trend: daylight steadily diminishes as the seasons change. The pattern is especially pronounced from October onwards, when daylight lasts for only 10 hours in October and further decreases through November. As we embrace the holiday season, the shrinking daylight serves as a reminder of winter's arrival, inviting the community to savor those precious hours of sunshine.

Average Daylight Hours in Rapid City for December

The chart illustrates the variation in daylight duration in Rapid City throughout the year, with December highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 18m10h 28m11h 57m13h 29m14h 46m15h 25m15h 4m13h 54m12h 26m10h 56m9h 36m8h 55m
Data source: Rapid City daylight hours, calculated by summing the hours between sunrise and sunset for each day.

December Winds in Rapid City

As December sweeps into Rapid City, the average wind speed settles at a brisk 3.9 m/s (9 mph), mirroring the conditions seen in both October and November. This consistency indicates a trend of slightly increased winds during the late fall and early winter months, providing a notable contrast to the calmer breezes of early winter. Compared to earlier months like July and August, where winds dipped below 3.4 m/s, December brings a refreshing increase in wind activity, hinting at the vibrant seasonal shifts that characterize life in this dynamic region. With each gust, the December winds capture the essence of Rapid City's rugged charm, inviting residents and visitors alike to embrace the crisp air amidst the scenic landscape.

Average December Wind Speed in Rapid City

The chart displays monthly wind speed patterns in Rapid City, with values for each month shown alongside December's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how December's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec4.03.23.74.03.43.43.23.23.43.93.93.9 m/s
Data source: Rapid City December wind data, generated using information from the Copernicus Climate Change Service.

How December Weather in Rapid City Compares to Other Months

The weather in Rapid City changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of December'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.

In December, temperatures in Rapid City range from a minimum of -23°C (-10°F) to a maximum of 21°C (70°F), with an average of -1°C (30°F). The month experiences about 28 mm (1.1 in) of precipitation over approximately 6 days, while humidity hovers around 75%. By contrast, January sees slightly colder conditions, with minimum temperatures dropping to -26°C (-14°F) and maximums reaching 16°C (61°F), resulting in an average of -3°C (27°F). Precipitation decreases to 14 mm (0.5 in) and occurs over just 4 days, accompanied by a slightly lower humidity of 73%. For more detailed information, visit Rapid City weather in January.

December and February display some intriguing similarities and differences in weather patterns. In December, temperatures range from a minimum of -23°C (-10°F) to a maximum of 21°C (70°F), averaging around -1°C (30°F). The month sees about 28 mm (1.1 in) of precipitation over approximately six days, with humidity levels at 75%. In contrast, February experiences slightly colder conditions, with minimum temperatures dropping to -29°C (-19°F) and an average of -6°C (22°F), while still peaking at 21°C (69°F). Precipitation in February is similar at 27 mm (1.1 in), but it occurs over more days, totaling seven, with humidity rising to 78%. For a detailed look at February weather, refer to Rapid City weather in February.

December and March present contrasting weather patterns, despite their proximity in the winter season. December typically experiences a milder average temperature of -1°C (30°F), with a maximum reaching up to 21°C (70°F) and a minimum of -23°C (-10°F). In contrast, March is slightly cooler on average at 2°C (36°F), with a minimum of -26°C (-14°F) and a similar maximum of 22°C (71°F). Precipitation is also more frequent in March, occurring over eight days compared to December's six days, with a total of 44 mm (1.7 in) in March versus 28 mm (1.1 in) in December. Additionally, the humidity is higher in December at 75%, while March sees a decrease to 64%. For more specific details on the weather conditions during this time, you can check Rapid City weather in March.

In December, temperatures can plummet as low as -23°C (-10°F), with an average of -1°C (30°F) and a maximum reaching up to 21°C (70°F). The month typically sees about 28 mm (1.1 in) of precipitation over roughly 6 days, accompanied by a relatively high humidity level of 75%. In contrast, April experiences milder conditions with minimum temperatures around -16°C (3°F) and an average of 5°C (41°F), peaking at 25°C (77°F). Precipitation increases to 73 mm (2.9 in) over 11 days, but humidity drops to 66%. For more details on the weather in April, you can visit Rapid City weather in April.

December and May present stark contrasts in weather patterns. In December, temperatures can plummet to a minimum of -23°C (-10°F) and average around -1°C (30°F), with occasional highs reaching 21°C (70°F). The month sees a relatively low precipitation level of 28 mm (1.1 in) over 6 days, coupled with a humidity of 75%. In comparison, May warms up significantly, with minimum temperatures of -4°C (24°F) and an average of 11°C (53°F), soaring up to a maximum of 30°C (86°F). However, May is much wetter, experiencing 112 mm (4.4 in) of precipitation over 17 days, while the humidity remains a similar 74%. This transition from chilly winter to a more temperate spring is vividly illustrated in Rapid City weather in May.

In December, the weather in Rapid City tends to be quite cold, with average temperatures hovering around -1°C (30°F) and a minimum that can drop as low as -23°C (-10°F). Precipitation during this month is relatively low at 28 mm (1.1 in) over approximately 6 days, and humidity levels are typically around 75%.

In stark contrast, June brings significantly warmer temperatures, with averages around 19°C (67°F) and maximums reaching as high as 36°C (97°F). The month sees more precipitation, totaling 72 mm (2.8 in) over approximately 13 days, along with higher humidity levels at 84%. For more detailed information, you can check out Rapid City weather in June.

The weather in December and July contrasts sharply in terms of temperature and precipitation. December brings frigid conditions with temperatures ranging from a chilling -23°C (-10°F) to a mild maximum of 21°C (70°F), while July enjoys a much warmer climate, with average temperatures hovering around 22°C (72°F) and highs reaching up to 38°C (100°F). Precipitation also differs significantly; December sees about 28 mm (1.1 in) over just 6 days, whereas July receives a substantial 96 mm (3.8 in) spread over 16 days, accompanied by higher humidity levels of 85%. For more details about July weather, visit Rapid City weather in July.

The weather in December contrasts significantly with that of August. December experiences frigid temperatures, with lows dropping to -23°C (-10°F) and an average temperature around -1°C (30°F), while August enjoys much milder conditions, with average temperatures reaching 20°C (69°F) and highs soaring up to 37°C (98°F). Additionally, December sees lower precipitation levels, with only 28 mm (1.1 in) over about 6 days, compared to August’s 57 mm (2.2 in) of rain over 12 days. Humidity is also higher in August at 85%, compared to December's 75%. For more detailed information, check out Rapid City weather in August.

When comparing the weather in December and September, we see notable differences in temperature and precipitation. December experiences a broader temperature range, with minimums plunging to -23°C (-10°F) and a maximum of 21°C (70°F), averaging around -1°C (30°F). In contrast, September offers milder conditions, with a minimum of -4°C (26°F) and a maximum soaring to 37°C (100°F), averaging 16°C (62°F). Precipitation is slightly lower in December at 28 mm (1.1 in) over 6 days, compared to September's 43 mm (1.7 in) over 7 days. Additionally, humidity levels remain quite similar, with December at 75% and September at 76%. For more details, check out Rapid City weather in September.

In comparing the weather of December and October, December typically experiences a colder climate with an average temperature around -1°C (30°F), compared to October's milder average of 7°C (45°F). December's minimum temperature can plunge to -23°C (-10°F), while in October, it remains higher at -18°C (-1°F). Additionally, October tends to see more precipitation, with 52 mm (2.0 in) over 8 days, compared to December's 28 mm (1.1 in) over 6 days. Despite December's slightly higher humidity at 75%, both months offer distinct weather experiences, with October generally being warmer and wetter. For more detailed information, you can check Rapid City weather in October.

In December, the weather experiences more variability compared to November, with minimum temperatures dipping to -23°C (-10°F) and maximums reaching up to 21°C (70°F). This contrasts with November's milder conditions, where minimums are slightly higher at -19°C (-2°F) and maximums peak at 24°C (75°F). Additionally, December sees an increase in precipitation, totaling 28 mm (1.1 in) over 6 days, compared to November's 17 mm (0.7 in) over 5 days. Humidity levels remain fairly consistent, with December at 75% and November slightly lower at 73%. For more details on November's weather, visit Rapid City weather in November.

Compare Rapid City's Climate with Cities Worldwide

Conclusion: What to Expect From December Weather in Rapid City

As December arrives in Rapid City, it ushers in a significant shift in weather patterns compared to the rest of the year. The air turns noticeably colder, with temperatures frequently dipping well below freezing, presenting a stark contrast to the milder months. With an average temperature around -1°C, this month experiences fewer sunny days, often cloaked in clouds and moisture, culminating in around six days of precipitation. The higher humidity levels can make the cold feel even more biting, leading to that quintessential winter chill. For those keen to understand more about the shifting seasons, Rapid City Climate provides a comprehensive overview of year-round weather patterns.