Last updated: February 24, 2025
In August, Boulder, Colorado experiences a vibrant summer climate characterized by maximum temperatures reaching 33°C (91°F) and an enjoyable average temperature of 19°C (67°F). While the warm days invite outdoor activities, the evenings offer a refreshing contrast with minimum temperatures dipping to 7°C (45°F). This month typically witnesses 67 mm (2.7 in) of precipitation over 13 days, providing crucial moisture that supports the region's lush landscapes. With a humidity level of 56%, August's weather in Boulder creates a balanced environment, making it a delightful time to explore the beauty of the Rockies.
In August, Boulder, United States experiences a warm embrace as the temperatures peak, with average highs reaching 33°C (91°F) and lows settling around 7°C (45°F). The month is characterized by a pleasing warmth that invites outdoor activities and social gatherings, with the average temperature hovering around 19°C (67°F). This pattern of warm days and cool nights sets August apart as a vibrant time, following the gradual heat build-up from June and July, and precedes the cooler transition into September. As summer begins to wane, the welcoming warmth of Boulder's August provides an ideal backdrop for enjoying the scenic beauty of the area before the chill of autumn arrives.
In August, Boulder experiences a notable shift in its weather patterns, receiving 67 mm (2.7 in) of precipitation over 13 days. This slightly lower rainfall compared to the preceding months of May and July, which boast much higher totals of 134 mm (5.3 in) and 71 mm (2.8 in) respectively, indicates a gradual decline in summer precipitation. Yet, the warmth of summer persists, keeping the region vibrant and lush. The consistent rainfall throughout the month contributes to a rich tapestry of greenery as the area transitions toward the drier months ahead. As the fall season approaches, August’s precipitation serves as a vital bridge, ensuring Boulder remains nourished even as cloud cover begins to thin out.
In Boulder, August brings a slight uptick in humidity, averaging around 56%, following the drier months of June and July, which recorded 58% and 52% respectively. This modest increase is indicative of a gradual shift as the summer gives way to fall, with humidity levels rising again in September to 65%. Notably, humidity in Boulder tends to be quite high during the winter months, peaking at 89% in December. As we trace the trends from January through August, it’s evident that the region experiences a significant drop in humidity during the summer, only to see levels climb as autumn approaches, showcasing the natural rhythm of Boulder’s climate.
In August, Boulder experiences an extreme UV Index of 11, with a burn time of just 10 minutes, highlighting the continued intensity of summer sun exposure. This month sees a slight decrease from the peak index of 12 recorded in June and July, yet it remains critical for residents and visitors to take sun safety precautions. The trend from the start of the year shows an upward trajectory, beginning with a moderate 4 in January, escalating to this high level by late summer. As fall approaches in September, the UV Index begins to drop to 10, indicating a gradual easing of solar intensity. To stay informed and enjoy the outdoors safely, check the details at Boulder UV Index.
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August in Boulder, United States, shines brightly with 351 hours of sunshine, a sparkling continuation of the summer season that peaks in July with 378 hours. As the days linger longer and the warmth of summer begins to wane, August still offers ample sunshine, outshining the previous months but slightly tapering off as autumn approaches. This month is part of a notable upward trend, showcasing increasing sunlight from the chilly 185 hours of January all the way through to June, before a gradual decline begins in September. The consistent summer sunshine fosters an inviting atmosphere, making Boulder a perfect destination for outdoor enthusiasts eager to soak in the warm rays before transitioning to the cooler fall days ahead.
In Boulder, the likelihood of sunny weather peaks in August, boasting an impressive 65% chance of sunshine. This marks a notable increase compared to the previous summer months, with July at 59% and June at 55%. As the summer progresses, the trend suggests a more favorable outlook for sun-seekers, which is further supported by September's high of 69%. This sunny disposition is part of a broader pattern where the latter half of the year, starting from June through October, consistently offers better chances for clear skies, making Boulder an appealing destination for outdoor enthusiasts in August.
In Boulder, Colorado, the sunlight dances through the months, peaking in the summer and gradually ebbing as fall approaches. August marks a slight retreat from July's abundance, with daylight lasting around 13 hours. This month serves as a transition, heralding the gradual shortening of days. From the deep winter lows of 9 hours of daylight in January and December, the city experiences a remarkable increase, hitting a summer high of 14 hours from May through July. As August unfolds, the longer days give way to a gentle decline, echoing the seasonal shift towards autumn with September bringing 12 hours of daylight. Each month beautifully illustrates nature's rhythm, with sunlight inviting adventure while it lasts.
In Boulder, Colorado, the August winds settle into a gentle rhythm, with average speeds reaching around 2.2 m/s (5 mph). This slight decrease from the breezy July days mirrors a broader summer trend, as wind speeds begin to stabilize after the year's peak in early winter. Notably, the wind quietly gains momentum as autumn approaches, with speeds gradually increasing in November and December. While August may not boast the strongest gusts, its soothing breezes provide a tranquil respite, making it a perfect time for outdoor activities that embrace the serenity of late summer before the brisk fall air arrives.
The weather in Boulder changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of August's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Boulder and find detailed weather information for every month.
August and January showcase a dramatic contrast in weather conditions. In August, temperatures range from a cool minimum of 7°C (45°F) to a warm maximum of 33°C (91°F), with an average of 19°C (67°F). The month experiences moderate precipitation of 67 mm (2.7 in) over 13 days and has a humidity level of 56%. In stark contrast, January is characterized by frigid temperatures, dipping as low as -24°C (-12°F), with an average of -3°C (26°F) and a maximum of 15°C (59°F). This winter month sees significantly less precipitation, totaling only 25 mm (1.0 in) over just 5 days, but the humidity is notably higher at 88%. For more detailed information on January weather, you can visit Boulder weather in January.
August and February present strikingly different weather patterns. August boasts mild temperatures, with a minimum of 7°C (45°F) and an average high of 33°C (91°F), while enjoying an average humidity of 56%. This month typically experiences 67 mm (2.7 in) of precipitation over 13 days, signaling the late summer rains. In sharp contrast, February is characterized by frigid conditions, where temperatures can dip as low as -26°C (-14°F) and typically hover around -4°C (26°F). It sees less precipitation, with only 36 mm (1.4 in) over 9 days, but higher humidity at 87%, creating a colder, more biting air. For those interested in the specifics of winter weather, more information can be found here: Boulder weather in February.
August and March present contrasting weather patterns, highlighting the extremes of the seasons. In August, temperatures range significantly from a chilly 7°C (45°F) at night to a warm 33°C (91°F) during the day, with an average of 19°C (67°F). The month sees a moderate level of precipitation, totaling 67 mm (2.7 in) over 13 days, accompanied by a relatively comfortable humidity level of 56%. Conversely, March is marked by cooler temperatures, with a minimum of -21°C (-5°F) and a maximum of 23°C (73°F), averaging just 2°C (35°F). The month experiences slightly lower precipitation at 62 mm (2.5 in) across 11 days, but higher humidity at 81%, providing a much more crisp atmosphere. For a more detailed look, you can explore Boulder weather in March.
When comparing the weather in August and April, notable differences emerge. August boasts an average temperature of 19°C (67°F), with highs reaching up to 33°C (91°F), while April's temperatures are significantly cooler, averaging just 5°C (42°F) and peaking at 24°C (75°F). Both months experience similar levels of precipitation, with August receiving 67 mm (2.7 in) over 13 days and April seeing 68 mm (2.7 in) over 12 days. However, April's higher humidity of 76% contrasts with August's more moderate 56%, contributing to the perception of dampness during the spring month. For a closer look at April weather specifics, you can refer to Boulder weather in April.
In comparing the weather between August and May, we see notable differences in temperature and precipitation. August typically features a much warmer climate, with temperatures ranging from a minimum of 7°C (45°F) to a maximum of 33°C (91°F) and an average of 19°C (67°F). In contrast, May experiences cooler conditions, with temperature highs peaking at 27°C (81°F) and lows dipping to -9°C (17°F), averaging around 10°C (50°F).
While May is characterized by higher precipitation, totaling 134 mm (5.3 in) over 16 days, August sees less rainfall at 67 mm (2.7 in) over 13 days. Additionally, humidity levels are slightly higher in May at 66%, compared to 56% in August. For those interested in a more detailed overview, consider checking this link: Boulder weather in May.
When comparing the weather in August and June, August tends to be warmer overall, with average temperatures around 19°C (67°F) and maximums reaching up to 33°C (91°F). In contrast, June has a slightly cooler average temperature of 17°C (63°F), although it can also reach a maximum of 34°C (93°F). Precipitation is relatively consistent between the two months, with June receiving about 74 mm (2.9 in) over 14 days and August seeing 67 mm (2.7 in) over 13 days. Humidity is slightly lower in August at 56%, compared to June’s 58%. For more details, you can check Boulder weather in June.
In comparing the weather between July and August, both months exhibit similar temperature ranges, with August showing a minimum of 7°C (45°F), an average of 19°C (67°F), and a maximum of 33°C (91°F), while July has a slightly higher average temperature of 20°C (68°F) and a maximum of 34°C (93°F). Precipitation levels are relatively close as well, with August receiving 67 mm (2.7 in) over 13 days compared to July's 71 mm (2.8 in) across 16 days. Notably, August has a marginally higher humidity at 56% versus July’s 52%. For further insights on July weather, you can explore Boulder weather in July.
August and September present a notable shift in weather patterns. In August, temperatures range from a minimum of 7°C (45°F) to a maximum of 33°C (91°F), with an average temperature of 19°C (67°F). The month experiences 67 mm (2.7 in) of precipitation over 13 days, and humidity sits at 56%. In contrast, September sees a drop in minimum temperatures to -4°C (25°F), while the maximum remains similar at 33°C (92°F) and the average decreases to 16°C (61°F). Precipitation is also lower in September at 42 mm (1.6 in) across just 8 days, with a slight increase in humidity to 65%. For more detailed information, check out Boulder weather in September.
In August, the weather is typically warmer, featuring temperatures that range from a minimum of 7°C (45°F) to a maximum of 33°C (91°F), with an average of 19°C (67°F). It tends to be more humid at 56% and experiences about 67 mm (2.7 in) of rain over 13 days. In contrast, October ushers in cooler temperatures, with a striking minimum of -20°C (-5°F) and an average temperature of 7°C (45°F), while the maximum reaches 26°C (79°F). The month sees less rainfall at 48 mm (1.9 in) across just 7 days but higher humidity levels at 76%. For more detailed insights, check out Boulder weather in October.
August and November showcase vastly different weather patterns. In August, temperatures range from a minimum of 7°C (45°F) to a hot maximum of 33°C (91°F), with an average of 19°C (67°F). This month experiences moderate precipitation of 67 mm (2.7 in) over approximately 13 days, and humidity levels are relatively comfortable at 56%. In stark contrast, November sees much cooler temperatures, with a minimum of -16°C (3°F), an average of just 2°C (36°F), and a milder maximum of 22°C (71°F). Precipitation is lower at 30 mm (1.2 in) over only 6 days, but humidity rises significantly to 82%, creating a much chillier atmosphere. For more detailed information, you can check Boulder weather in November.
August and December present strikingly different weather conditions. In August, temperatures range from a cool 7°C (45°F) at night to a warm maximum of 33°C (91°F) during the day, accompanied by moderate precipitation totaling 67 mm (2.7 in) over about 13 days, with humidity averaging 56%. In contrast, December experiences much colder weather, with temperatures dropping significantly to a minimum of -19°C (-1°F) and averaging around -2°C (29°F), while the maximum is capped at 19°C (67°F). The month sees far less precipitation, totaling just 19 mm (0.8 in) over only 4 days, and a higher humidity level of 89%. For a deeper look into weather specifics, you can check Boulder weather in December.
As summer winds down, August in Boulder showcases a delightful blend of warmth and moisture. Unlike the scorching days of July, temperatures tend to be more moderate, offering a comfortable average of 19°C while occasionally spiking to a maximum of 33°C. The month is marked by increased precipitation, with 13 days recording light rain, contributing to a vibrant landscape. This combination of 56% humidity and intermittent showers creates a refreshing reprieve compared to the drier months of June and July, inviting both locals and visitors to relish the beauty of Boulder before the autumn chill sets in. For further insights into what to expect throughout the year, explore more at Boulder Climate.