Last updated: February 24, 2025
May weather in Keystone, United States, presents a blend of cool temperatures and moderate precipitation. During this month, the maximum temperature reaches around 17°C (63°F), while the average hovers at a brisk 2°C (35°F), and the minimum can drop to a chilly -13°C (10°F). With 81 mm (3.2 in) of rain spread across 14 days, residents and visitors alike can expect a mix of damp and cool conditions, complemented by a humidity level of 66%. This unique weather pattern sets the stage for dynamic outdoor experiences and vibrant spring scenery.
In May, Keystone, South Dakota, begins to shed the lingering chill of winter, displaying a noticeable warming trend as temperatures climb. With minimums hovering around -13°C (10°F) and average temperatures reaching 2°C (35°F), the month showcases a significant shift from the harsh cold of earlier months. Sunlight becomes more abundant, inviting highs that can peak at a pleasant 17°C (63°F), making it a time of vibrant change. This progression reflects a clear transition from the frigid depths of winter through the gradual warmth of spring, setting the stage for the warmer months ahead and transforming the landscape into a lush playground for outdoor enthusiasts.
In May, Keystone experiences a lively uptick in precipitation, accumulating 81 mm (3.2 in) over 14 days. This increase builds upon the steady rise from earlier months, such as 78 mm (3.1 in) in April. The precipitation in May not only marks the beginning of the region's lush summer growth but also represents a consistent pattern of spring rainfall, which peaks just before the drier summer months. As residents prepare for the warmer days ahead, this transition encapsulates the vibrant and refreshingly wet nature of May in Keystone, paving the way for both blooming flora and the promise of outdoor adventures.
As spring blossoms into summer, May in Keystone, United States, brings a notable drop in humidity, settling at 66%. This shift marks a significant decline from the wetter months of winter, where January and February see humidity levels hovering around 88% and 87% respectively. The transition continues through April, which experiences a decrease to 76%, setting the stage for the drier warmth of June at 58%. This downward trend reflects the region's journey from the crisp, moisture-laden air of winter towards the drier summer months, creating a refreshing atmosphere that is perfect for outdoor activities. As humidity eases, residents and visitors alike can look forward to enjoying the beautiful landscapes of Keystone under sunnier skies.
In May, Keystone experiences a notably high UV Index of 13, categorizing it as extreme with a burn time of only 10 minutes. This marks a continuation of the trend set in April, where the UV Index also reached 12. As the spring progresses, residents and visitors alike should be aware that sun exposure becomes increasingly hazardous, leading into the summer months. The UV Index peaks further in June with an even higher reading of 14 before gradually tapering off in subsequent summer months. As the season changes, it's crucial to stay informed about sun safety—take necessary precautions to protect your skin from harmful rays. For more detailed information, check out Keystone UV Index.
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As the calendar turns to May, Keystone, United States, basks in a glorious 355 hours of sunshine, marking a stunning peak in daylight hours that sets the stage for outdoor adventures. This bright month is a continuation of an upward trend that began in the colder months; January's modest 183 hours climbs steadily through spring, reaching 316 hours in April. The sunshine not only uplifts spirits but also signals the arrival of vibrant wildflowers and bustling wildlife, inviting locals and visitors alike to indulge in the natural beauty of the area. This surge continues into June and July, where residents enjoy the maximum sunlight with 382 hours, making early summer the season to revel in nature's warmth.
In Keystone, United States, the likelihood of sunny weather begins to shift noticeably as spring advances into summer. May sees a sunny day probability of 42%, which is slightly below the seasonal average, as the region transitions from the relatively brighter April with 51% sunshine. While the chance of sunny days dips in May, a clear upward trend is evident as the months progress, culminating in the sunniest weather during August at 61%. As summer approaches, residents and visitors alike can look forward to increasingly brighter days, making the later months more appealing for outdoor activities.
As spring transitions into summer in Keystone, United States, daylight duration experiences a significant upward trend, peaking during the months of May through July. In May, residents can enjoy approximately 14 hours of daylight, a remarkable increase from the 9 hours in January. This pattern of extended daylight not only brightens the longer days of early summer but also encourages outdoor activities and community gatherings. As summer begins to wane, daylight gradually decreases, dipping back to 13 hours in August before settling at 12 hours in September. This cyclical dance between light and darkness highlights the changing seasons, offering a splendid reminder of nature's rhythm throughout the year.
In May, Keystone experiences an average wind speed of 2.4 m/s (5 mph), which reflects a slight dip from the spring months of April and March, where wind speeds were a bit brisker. The trend for this time of year suggests a gentle transition as the region heads toward summer, characterized by increasingly calmer conditions. This decrease aligns with the pattern noted in June and July, where wind speeds further diminish, reaching their lowest points. Overall, May offers a serene atmosphere, ideal for enjoying the stunning natural beauty of Keystone, while also signaling a shift towards the quieter breezes of summer.
The weather in Keystone changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of May's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Keystone and find detailed weather information for every month.
In comparing the weather of May and January, it's evident that May offers a much milder climate with an average temperature of 2°C (35°F), contrasted with January's frigid average of -11°C (13°F). While May sees temperatures ranging from a minimum of -13°C (10°F) to a pleasant maximum of 17°C (63°F), January's temperatures are notably colder, with a minimum of -26°C (-15°F) and a maximum of only 5°C (42°F). Additionally, May experiences more precipitation, totaling 81 mm (3.2 in) over about 14 days, while January has less precipitation at 41 mm (1.6 in) across 10 days. It's worth noting that January tends to be more humid, with a humidity level of 88%, compared to May's 66%. For more information on January weather in Keystone, you can visit Keystone weather in January.
May and February present stark contrasts in weather conditions. In February, temperatures can plunge to a minimum of -28°C (-19°F), with an average of -10°C (14°F) and a maximum of just 9°C (48°F), creating a consistently cold environment. In contrast, May experiences milder temperatures, ranging from a minimum of -13°C (10°F) to an average of 2°C (35°F) and reaching highs of 17°C (63°F). Additionally, February sees slightly less precipitation at 59 mm (2.3 in), while May has higher precipitation of 81 mm (3.2 in), despite both months having precipitation on 14 days. The humidity is also notably higher in February at 87% compared to May's 66%. For more information about the February weather, check out Keystone weather in February.
In comparing the weather of May and March, it's evident that May presents a more moderate climate. March experiences colder temperatures, with averages around -5°C (22°F) and minimums plunging to -25°C (-12°F), while May offers a significantly milder range from a minimum of -13°C (10°F) to an average of 2°C (35°F), peaking at a comfortable 17°C (63°F). Precipitation levels are similar, with May receiving 81 mm (3.2 in) compared to March’s 67 mm (2.7 in), but both months demonstrate rainfall over 14 days. Humidity is slightly higher in March at 81%, compared to 66% in May. For more details about March weather in Keystone, you can visit Keystone weather in March.
In comparing the weather of May and April, we see a noticeable warming trend. May experiences milder temperatures, with a minimum of -13°C (10°F) and an average of 2°C (35°F), compared to April's colder minimum of -21°C (-5°F) and average of -3°C (27°F). Moreover, May boasts a higher maximum temperature of 17°C (63°F) versus April's 10°C (50°F), signaling a significant shift towards more spring-like conditions. Precipitation levels are similar, with May recording 81 mm (3.2 in) over 14 days and April slightly less at 78 mm (3.1 in) over 13 days. Interestingly, humidity is also lower in May at 66%, compared to 76% in April, suggesting drier air as the month progresses. For more specific information, you can refer to Keystone weather in April.
May and June present a notable shift in weather conditions. In May, temperatures range from a chilly minimum of -13°C (10°F) to a maximum of 17°C (63°F), with an average of just 2°C (35°F). The month also sees considerable precipitation, totaling 81 mm (3.2 in) over 14 days, contributing to a higher humidity level of 66%. In contrast, June brings warmer weather, with temperatures ranging from a low of -9°C (15°F) to a high of 24°C (75°F) and an average of 8°C (46°F). Additionally, June experiences less precipitation at 50 mm (2.0 in) over 10 days and a reduction in humidity to 58%. For more details on June weather specifics, you can explore Keystone weather in June.
May and July present distinct differences in weather conditions. In May, temperatures average around 2°C (35°F) with a maximum of 17°C (63°F), while July sees a warmer average of 11°C (53°F), reaching up to 23°C (74°F). Precipitation levels are relatively similar, with May receiving 81 mm (3.2 in) over 14 days and July slightly higher at 83 mm (3.3 in) over 15 days. However, the humidity drops from 66% in May to 52% in July, creating a more comfortable atmosphere during the summer month. For more details on July weather, check out Keystone weather in July.
May and August present a stark contrast in weather patterns. In May, temperatures exhibit a broader range, with minimums dropping to -13°C (10°F) and maximums reaching 17°C (63°F), resulting in an average temperature of 2°C (35°F). The month is also quite wet, with total precipitation of 81 mm (3.2 in) over 14 days and humidity levels hovering around 66%. In contrast, August brings warmer conditions, with temperatures consistently higher, ranging from a minimum of 0°C (32°F) to a maximum of 22°C (73°F), yielding an average of 11°C (52°F). The precipitation is lighter in August, at 53 mm (2.1 in) over just 11 days, with lower humidity at 56%. For more detailed insights on August weather, you can explore Keystone weather in August.
May and September present distinct weather patterns, demonstrating the transition between spring and autumn. May typically features cooler temperatures, with an average of 2°C (35°F) and maximums reaching 17°C (63°F), while September enjoys a milder average of 7°C (46°F) and maximums of 22°C (72°F). Additionally, May experiences more precipitation at 81 mm (3.2 in) over approximately 14 days, compared to September's more moderate 43 mm (1.7 in) across 9 days. Humidity levels remain similar, with May at 66% and September slightly lower at 65%. For more specific weather insights, you can check Keystone weather in September.
May and October showcase distinct weather characteristics, with May generally being milder. In May, temperatures range from a minimum of -13°C (10°F) to a maximum of 17°C (63°F), with an average of 2°C (35°F). This month experiences higher precipitation levels at 81 mm (3.2 in) over approximately 14 days, with a humidity level of 66%. In contrast, October witnesses colder conditions, with temperatures dipping as low as -24°C (-10°F) at night, while daytime highs can still reach 17°C (63°F), averaging around -1°C (31°F). Precipitation in October is lower, at 56 mm (2.2 in) over about 9 days, accompanied by a higher humidity level of 76%. For more detailed insights, check out Keystone weather in October.
May and November present starkly different weather conditions. In May, temperatures range from a chilly -13°C (10°F) at night to a comfortable 17°C (63°F) during the day, with an average of 2°C (35°F). The month sees around 81 mm (3.2 in) of precipitation over 14 days, coupled with a humidity level of 66%. In contrast, November is significantly colder, with temperatures dropping from -27°C (-17°F) to a maximum of 10°C (50°F), averaging -7°C (20°F). Precipitation declines to 41 mm (1.6 in) over just 8 days, while humidity rises to 82%. For more details on November weather, you can check Keystone weather in November.
May and December present stark contrasts in weather conditions. In May, temperatures range from a brisk -13°C (10°F) to a mild 17°C (63°F), with an average of 2°C (35°F). The month experiences more precipitation, with about 81 mm (3.2 in) falling over 14 days, and humidity is moderate at 66%. In contrast, December is significantly colder, with temperatures ranging from a frigid -29°C (-20°F) to a maximum of 8°C (47°F), averaging -11°C (13°F). Precipitation is less frequent in December, totaling 43 mm (1.7 in) over just 10 days, and the humidity is higher at 89%. For more specific insights into December weather conditions, you can explore Keystone weather in December.
In May, Keystone experiences a noticeable transition as winter's chill gives way to the anticipation of warmer days. With average temperatures hovering around a brisk 2°C, the area remains cooler compared to the summer months, while still offering a pleasant respite from the biting cold of early spring. The 81 mm of precipitation spread over 14 days means you might encounter a shower or two, but these spring rains often bring vibrant green landscapes. Coupled with a humidity level of 66%, May's weather sets the stage for a refreshing alpine experience unlike any other month. For a deeper dive into what to expect throughout the year, check out Keystone Climate.