Last updated: February 24, 2025
April in Boulder, United States, brings a dynamic range of weather as temperatures fluctuate from a maximum of 24°C (75°F) to a minimum of -17°C (2°F), with an average of 5°C (42°F). This month experiences notable precipitation, accumulating 68 mm (2.7 in) over 12 days, contributing to the region's lush landscapes. With humidity averaging 76%, the air can feel quite crisp, accentuating the charm of spring's awakening in the foothills. Whether basking in warmer afternoons or bracing against cooler nights, April showcases the diverse climate that Boulder is known for.
April in Boulder, United States, marks a notable transition as winter gives way to the hints of spring. With minimum temperatures averaging around -17°C (2°F) and daytime highs reaching a pleasant 24°C (75°F), the month showcases a significant warming trend compared to the chill of March. April's average temperature dips slightly above 5°C (42°F), signifying a steady progression toward milder conditions. As residents shake off the lingering frost, the increasing warmth encourages outdoor activities and offers a vibrant backdrop of emerging blooms, making it a delightful time to experience Boulder’s natural beauty and fresh beginnings.
In April, Boulder experiences a significant uptick in precipitation, marking the transition into spring with an average of 68 mm (2.7 in), delivered over 12 days of rain. This increase follows March's 62 mm (2.5 in) and sets the stage for May's peak of 134 mm (5.3 in), highlighting a distinct upward trend as warmer temperatures and melting snow contribute to the city's overall moisture levels. The steady rise in rainfall throughout these months not only nourishes the blossoming landscape but also prepares Boulder for the lush growth of spring. As the days grow longer and the weather warms, April serves as a vital precursor to the wetter, more vibrant months ahead.
In April, Boulder experiences a noticeable shift in humidity as it drops to 76%, continuing a trend of decreasing moisture levels that began in March. This reflects a gradual transition into drier spring conditions, with humidity steadily declining from the 88% seen in January. As the month progresses towards warmer weather, you'll find that May brings even greater relief, with humidity levels falling to 66%. This pattern of reducing humidity is typical for Boulder's climate, creating a refreshing atmosphere as the landscape awakens from winter's grip and prepares for the warmth of summer.
As April unfolds in Boulder, the UV Index reaches a striking 11, signaling an extreme exposure category and a burn time of just 10 minutes. This surge in UV intensity marks a significant increase from the previous months, where January's moderate Index of 4 and February's high Index of 6 offered a false sense of security. Transitioning through March, outdoor enthusiasts experienced a jump to a very high Index of 9, but April catapults into the realm of extreme UV exposure, emphasizing the need for heightened sun safety precautions. This pattern of rising UV levels not only continues into May but also maintains its apex with an Index of 12 during the peak summer months of June and July. Staying informed about these trends is crucial for enjoying the beautiful Colorado outdoors while protecting your skin. For more details, check out the comprehensive Boulder UV Index.
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April brings a delightful surge of sunshine to Boulder, with 304 hours of radiant daylight, marking a significant leap from the previous months. As winter transitions to spring, the city experiences a noticeable increase in sunlight after January's somber 185 hours. This trend continues from March, which sees 288 hours of sun, setting the stage for April’s glow. The month not only showcases the blooming beauty of nature but also heralds the approach of even sunnier days ahead, culminating in May’s impressive 330 hours. This gradual climb in daylight paves the way for bright summer months, making Boulder a vibrant haven for outdoor enthusiasts and sun seekers alike.
In Boulder, April brings a moderate likelihood of sunny weather, with about 51% of days typically basking in sunlight. This percentage reflects a slight dip from the 50% in March, but it's interesting to note that sunny days are on the rise as the season progresses. As the year unfolds, May experiences a further decline to 41%, making April one of the last months of the spring season to enjoy a relatively balanced share of sunshine before summer's higher probabilities kick in. Looking ahead, the chance of sunny days increases significantly in the summer months, peaking at 65% in August. Thus, while April may not be the sunniest month, it serves as a transitional period that gently ushers in more radiant days ahead.
As spring unfolds in Boulder, the length of daylight dramatically increases, providing a vibrant backdrop for outdoor activities. April marks a significant leap in daylight duration, enjoying an average of 13 hours of sunlight, a notable rise from 11 hours in March. This trend continues into May, where daylight reaches its peak at 14 hours. As the months progress into summer, Boulder basks in this ample sunlight, enjoying the same 14 hours from June through July, making these months particularly enchanting for those who relish long days. However, as summer fades, the hours of daylight begin to recede, dropping back to 13 hours in August and tapering off gradually into the fall. With winter approaching, the daylight dwindles back to 9 hours by December, completing a natural cycle that showcases the changing seasons and invites residents to savor every moment of the sun-drenched spring and summer days.
As April arrives in Boulder, the wind takes on a slightly gentler tone, with an average speed of 2.4 m/s (5 mph)—just a notch below the breezy months of January through March. This gradual decline reflects a trend toward calmer spring weather, offering a serene backdrop for the stunning blooms and vibrant outdoor activities that define the season. While the winds may be softer in April, they are mirrored by a slight uptick in speeds in the following months, hinting at a return to brisker gusts as summer approaches. Overall, April's breezy character showcases a delicate balance—providing just enough whispering winds to invigorate the senses without overshadowing the beauty of Boulder in bloom.
The weather in Boulder changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of April'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.
April and January present significantly different weather conditions. In April, temperatures range from a minimum of -17°C (2°F) to a pleasant maximum of 24°C (75°F), with an average of 5°C (42°F). This month experiences 68 mm (2.7 in) of precipitation over about 12 days, accompanied by a humidity level of 76%. In contrast, January tends to be colder, with a minimum temperature of -24°C (-12°F) and a maximum of 15°C (59°F), averaging -3°C (26°F). Additionally, January sees less precipitation, totaling 25 mm (1.0 in) across just 5 days, along with a higher humidity of 88%. For more details, you can visit Boulder weather in January.
April's weather contrasts sharply with that of February, showcasing a significant warming trend. While February experiences a minimum temperature of -26°C (-14°F) and an average of -4°C (26°F), April boasts a more temperate climate with minimums of -17°C (2°F) and an average of 5°C (42°F). Additionally, April can see maximum temperatures rise to 24°C (75°F), compared to February's peak of 20°C (69°F). Precipitation is also more frequent in April, with 68 mm (2.7 in) over 12 days, while February has lower precipitation levels at 36 mm (1.4 in) over 9 days. Thus, April begins to shed the winter chill, although it remains on the humid side, with April's humidity at 76% versus February's 87%. For a closer look at February's climate, visit Boulder weather in February.
April weather in Boulder shows a notable warming trend compared to March. While March experienced a minimum temperature of -21°C (-5°F) and an average of 2°C (35°F), April's temperatures start to rise with a minimum of -17°C (2°F) and an average of 5°C (42°F). Despite both months nearing similar maximum temperatures, with March reaching 23°C (73°F) and April peaking at 24°C (75°F), April tends to be slightly wetter, receiving 68 mm (2.7 in) of precipitation over 12 days compared to March's 62 mm (2.5 in) over 11 days. Additionally, April's humidity of 76% is marginally lower than March's 81%, creating a more comfortable environment. For a more detailed comparison, you can check Boulder weather in March.
In comparing the weather from April to May, we see a noticeable shift towards warming temperatures and increased precipitation. April features a temperature range with a minimum of -17°C (2°F) and a maximum of 24°C (75°F), leading to an average of 5°C (42°F). In contrast, May brings milder conditions, with temperatures ranging from -9°C (17°F) to 27°C (81°F), resulting in an average temperature of 10°C (50°F). Furthermore, May experiences a significant increase in precipitation, totaling 134 mm (5.3 in) over 16 days, compared to April's 68 mm (2.7 in) across 12 days. Additionally, humidity levels are slightly lower in May at 66% versus April’s 76%. For more detailed information, you can check Boulder weather in May.
April and June display notable differences in weather patterns. In April, temperatures range from a chilly minimum of -17°C (2°F) to a pleasant maximum of 24°C (75°F), with an average temperature of 5°C (42°F). The month experiences 68 mm (2.7 in) of precipitation over approximately 12 days, and the humidity is relatively high at 76%. In contrast, June sees milder minimum temperatures at 3°C (37°F) and a significant rise in average temperature to 17°C (63°F), with maximums reaching a warm 34°C (93°F). Interestingly, June has slightly higher precipitation at 74 mm (2.9 in), spread over 14 days, but lower humidity at 58%. For more details, check out this link: Boulder weather in June.
April's weather is characterized by a wide temperature range, with minimums plummeting to -17°C (2°F) and maximums reaching 24°C (75°F). The month experiences an average temperature of 5°C (42°F) and sees significant precipitation on 12 days, contributing to a relatively high humidity of 76%. In contrast, July offers much warmer conditions, with minimum temperatures of 7°C (45°F) and maximums soaring to 34°C (93°F), averaging around 20°C (68°F). Although July experiences slightly higher precipitation at 71 mm (2.8 in) over 16 days, the overall humidity drops to a more comfortable 52%. For more details about July weather, you can check Boulder weather in July.
April and August present contrasting weather experiences. In April, temperatures range from a chilly minimum of -17°C (2°F) to a pleasant maximum of 24°C (75°F), with an average of 5°C (42°F). Precipitation is relatively high at 68 mm (2.7 in) over 12 days, and the humidity averages a significant 76%. On the other hand, August boasts milder temperatures with a minimum of 7°C (45°F) and a maximum reaching up to 33°C (91°F), while the average sits at 19°C (67°F). Although precipitation is similar at 67 mm (2.7 in) over 13 days, the humidity drops to a comfortable 56%. For more details on August’s weather, you can visit Boulder weather in August.
April and September present contrasting weather patterns. In April, temperatures can dip as low as -17°C (2°F) and peak at around 24°C (75°F), with an average temperature of 5°C (42°F). The month also sees an average of 68 mm (2.7 in) of precipitation spread over 12 days, contributing to a higher humidity level of 76%. In comparison, September offers milder conditions with minimum temperatures of -4°C (25°F) and highs reaching up to 33°C (92°F), resulting in a more pleasant average of 16°C (61°F). This month experiences less precipitation, totaling 42 mm (1.6 in) over just 8 days, along with a lower humidity of 65%. For a detailed overview of the typical climate, you can check Boulder weather in September.
April and October both exhibit a range of temperatures and similar humidity levels, but they present distinct weather characteristics. In April, temperatures can drop as low as -17°C (2°F) and reach a pleasant maximum of 24°C (75°F), with an average temperature of 5°C (42°F). The month sees about 68 mm (2.7 in) of precipitation spread over 12 days. In contrast, October experiences slightly colder minimum temperatures of -20°C (-5°F) and slightly warmer maximums of 26°C (79°F), with an average of 7°C (45°F). Precipitation in October is lower at 48 mm (1.9 in), occurring on just 7 days. Both months share a humidity level of 76%, but the overall feel of October's weather can be crisper and more stable compared to April's variability. For more details on October weather in Boulder, you can check Boulder weather in October.
April and November offer distinct weather characteristics despite their proximity in the calendar year. In April, temperatures range from a chilly minimum of -17°C (2°F) to a pleasant maximum of 24°C (75°F), with an average of 5°C (42°F) and higher humidity at 76%. This month experiences more significant precipitation, totaling 68 mm (2.7 in) over about 12 days. Conversely, November typically sees slightly warmer conditions at the maximum (22°C or 71°F) and a less extreme minimum of -16°C (3°F), resulting in a lower average temperature of 2°C (36°F). The month is generally drier, with only 30 mm (1.2 in) of precipitation over 6 days and slightly higher humidity at 82%. For more specific insights on the weather, check out Boulder weather in November.
April and December exhibit striking contrasts in weather conditions. In April, temperatures range from a chilly minimum of -17°C (2°F) to a pleasant maximum of 24°C (75°F), with an average of 5°C (42°F). The month sees about 68 mm (2.7 in) of precipitation over 12 days, and humidity levels sit at 76%. In contrast, December features colder temperatures, with a minimum of -19°C (-1°F) and an average of -2°C (29°F), peaking at 19°C (67°F). Precipitation is significantly lower in December, at 19 mm (0.8 in) over just 4 days, and the humidity rises to 89%. For more details, check Boulder weather in December.
April in Boulder marks a dynamic transition from the chill of winter to the warmth of spring, showcasing a range of temperatures that oscillate from crisp, chilly nights to pleasantly mild days. With average temperatures sharply rising compared to the cold winter months, this month brings a noticeable shift in the climate. However, April also contributes to the total annual precipitation, with rain falling on about half the month. Humidity levels rise, further contributing to the evolving atmosphere. Discover more about the distinct characteristics of Boulder’s climate throughout the year by visiting Boulder Climate.