Climate and monthly weather forecastBoulder, WY
Climate and monthly weather forecast
The climate of Boulder
Boulder, Wyoming, USA aligns with the Humid Continental, No Dry Season, Warm Summer climate, as per the Köppen climate classification. This climate grouping is known as Dfb. The geographical position, nestled in the foothills of the Rocky Mountains, significantly impacts the climate patterns witnessed here.The weather in Boulder experiences a wide range of diversity throughout the year. A notable shift in temperatures can be observed with summer highs peaking at 78.4°F (25.8°C) in July, while the winters bring in much colder lows falling to 5.4°F (-14.8°C) in January. The relative humidity ranges from a low of 34% in August up to a high of 86% in February. The disparity between the warmest and coldest months is rather pronounced, further accentuating the distinct seasonal variations.
Rainfall is mostly consistent throughout the year, with the maximum average recorded in May at 1.73" (44mm), and the smallest amount observed in December, at 0.55" (14mm). The number of rainy days ranges from 5.5 days in January up to 15.2 days in May. On the other hand, snowfall is prevalent during winter months with January seeing 5.08" (129mm) of snow over 10.2 days, and greatly diminishing as the seasons change with zero inches from June to August.
Unique weather conditions arise from the daylight hours that fluctuate from a maximum of 15.3 hours in June to a mere 9.1 hours in December. This drastic variation influences other aspects such as sunshine hours, which peak from June to August with 11.8 to 11.9 hours and dip in January providing only 6.3 hours of sunshine.
The best time to visit Boulder
The optimal time to visit Boulder depends largely on personal preferences relating to climate. If outdoor activities and warmer weather are prized, summertime, between June and August, is the best fit with daily highs averaging between 67.3°F (19.6°C) and 78.4°F (25.8°C). These months offer around 15 hours of daylight, ensuring that visitors can make the most of their days. Moreover, the humidity levels are relatively low during this timeframe, providing comfort and ease for tourists.The worst time to visit Boulder
December and January arguably represent less favourable times to visit Boulder, due to harsher weather conditions. Along with the lowest high and low temperatures hovering around 23.9°F (-4.5°C) and 5.4°F (-14.8°C) respectively, these months also witness sizable snowfall, accumulating up to 5.08 and 7.32" (186mm), which could inhibit travel and access to various activities.Spring weather in Boulder
Spring in Boulder witnesses a remarkable shift in climatic conditions. Temperatures begin to rise from lows of 17.8°F (-7.9°C) in March to a mild 38.3°F (3.5°C) by May. The daylight hours steadily expand from an average of 12 hours in March to 14.7 hours in May. Rainfall also increases during this period, with May recording the highest rainfall averaging 1.73" (44mm) over 15.2 days.Summer weather in Boulder
The summer period from June to August provides warm and comfortable weather in Boulder. High temperatures range from 67.3°F (19.6°C) to 78.4°F (25.8°C), whereas the lows vary from 47.5°F (8.6°C) to 55.2°F (12.9°C). With nearly 15 hours of daylight, summer boasts the longest days. The humidity drops during these months, resulting in relatively dry weather, making this season perfect for outdoor activities and tourism.Autumn weather in Boulder
Shifting into autumn, Boulder’s temperatures begin to plummet with high temperatures moving from 67.3°F (19.6°C) in September down to 36.1°F (2.3°C) in November. Concurrently, the low temperatures descend from 46.9°F (8.3°C) to 19.6°F (-6.9°C). Precipitation remains consistent during this season, and daylight hours progressively shorten from 12.5 hours in September to 9.8 hours in November.Winter weather in Boulder
Winter in Boulder is characterized by cold temperatures, with highs below freezing and lows falling to 5.9°F (-14.5°C) in December. The visibility average remains constant at 5 miles, despite the shorter daytime hours which range from 9.8 hours in December to 9.1 hours in January. Snowfall is prevalent during this season, with December recording an average of 4.33" (110mm) over a period of 13.5 days.Weather in January
Kickstarting the year, Boulder's weather in January tends to be severe due to frigid temperatures and higher frequency of snowfall. A low temperature could drop to 5.4°F (-14.8°C), making it one of the coldest months of the year. Weather in January »Weather in February
Moving into February, winter still clings to Boulder, Wyoming with slightly raised temperatures compared to January. This second month of the year witnesses a drastic snowfall shift, ascending to 7.32" (186mm). Despite the brightness from the snow, February experiences a fair share of cloudy days limiting sunshine hours. Weather in February »Weather in March
March brings a noticeable transformation in Boulder's weather with an uplift from the harsh winter. A rise in both high and low temperature averages is the first sign of impending spring. This month's predominant characteristic is a drop in snowfall to 7.05" (179mm) compared to February. Weather in March »Weather in April
Boulder silently ushers in spring come April. With a significant increase of up to 45°F (7.2°C) in high temperatures, this month marks a clear departure from the preceding chilly period. There is also a noticeable decline in snowfall to 6.97" (177mm), although April is still dominated by cooler weather. Weather in April »Weather in May
May sets the stage for mild spring weather in Boulder. This month springs forth with the highest rainfall, recording an average of 1.73" (44mm). The increase in rainfall in combination with extended daylight hours supports faster green growth. Weather in May »Weather in June
June, being Boulder's warmest thus far, celebrates the arrival of summer, boosting high temperatures to an average of 69.6°F (20.9°C). Compared to May, on the flip side, this month displays a noticeable cutback in precipitation, observing only 0.91" (23mm). Weather in June »Weather in July
July sizzles as the hottest month of the year in Boulder, Wyoming, with temperatures soaring to 78.4°F (25.8°C) on average. The conditions consolidate summer, with lower rainfall scales recording an average of 0.55" (14mm). Extended sunshine hours are complemented by reduced cloud cover, creating an inviting atmosphere for outdoor activities. Weather in July »Weather in August
The weather takes a slight downturn in August, a mild respite after the July blaze. High temperatures witness a minor drop, descending slightly to 76.6°F (24.8°C). The landscape remains devoid of snow, affirming the summer season. Weather in August »Weather in September
Boulder transitions into autumn in September, carrying with it a drop in temperatures. A prominent decrease in high temperatures to an average of 67.3°F (19.6°C) marks the transition from summer. The changing weather is marked by a slight uptick in rainfall by 0.79" (20mm). Weather in September »Weather in October
In October, Boulder takes a deeper plunge into autumn, with further dropping temperature averages. A re-emergence of snowfall occurs, recording an average of 2.52" (64mm), announcing the imminent arrival of winter. While it has shorter days and more cloudy periods, there is still an abundance of sunlight. Weather in October »Weather in November
November illustrates an unequivocal shift to colder weather conditions in Boulder, Wyoming. The snowfall increase to 5.16" (131mm) accompanying the drastic temperature drop corroborates the winter season's onset. Despite the winter creep, the town still enjoys a fair share of sunny days. Weather in November »Weather in December
Boulder bids the year farewell with a return to harsh winter conditions in December. The cold intensifies with temperatures dipping further to a monthly mean low of 5.9°F (-14.5°C), closing the year on a frosty note. Plus, a snowfall increment to 4.33" (110mm) accentuates the winter atmosphere. Weather in December »Updated: Feb 14, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Throughout the year, in Boulder, there are 102.6 rainfall days, and 10.75" (273mm) of precipitation is accumulated.
January through June, September through December are months with snowfall in Boulder.
Throughout the year, there are 86.8 snowfall days, and 41.77" (1061mm) of snow is accumulated.
The month with the least sunshine is January, with an average of 6.3h of sunshine.
January through April, October through December, with an average maximum UV index of 2, are months with the lowest UV index.
With an average relative humidity of 86%, February is the most humid month in Boulder, Wyoming.
The month with the most snowfall in Boulder, Wyoming, is February, when snow falls for 14.7 days and typically aggregates up to 7.32" (186mm) of snow.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Boulder, Wyoming, and the time zone changes from MST to MDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from MDT to MST.
May is the month with the most rainfall in Boulder, Wyoming. Rain falls for 15.2 days and accumulates 1.73" (44mm) of precipitation.
With an average of 15h and 18min of daylight, June has the longest days of the year in Boulder.
The highest temperatures are recorded in July, with averages reaching a high of 78.4°F (25.8°C) and a low of 55.2°F (12.9°C).
In Boulder, snow does not fall in July and August.
The months with the most sunshine in Boulder are July and August, with an average of 11.9h of sunshine.
July is the month with the highest UV index in Boulder, with an average maximum UV index of 6.
With an average relative humidity of 34%, August is the least humid month in Boulder, Wyoming.
August is the month with the least rainfall in Boulder. Rain falls for 7.1 days and accumulates 0.51" (13mm) of precipitation.
December proves to be the coldest month in Boulder, recording an average maximum temperature of 23.9°F (-4.5°C) and a minimum temperature of 5.9°F (-14.5°C).
The month with the shortest days is December, with an average of 9h and 6min of daylight.
Average temperature
Boulder, WY
The warmest month (with the highest average high temperature) is July (78.4°F).
The month with the lowest average high temperature is December (23.9°F).
The month with the highest average low temperature is July (55.2°F).
The coldest month (with the lowest average low temperature) is January (5.4°F).
Average pressure
Boulder, WY
- Average pressure in January:
30.27"Hg - Average pressure in February:
30.16"Hg - Average pressure in March:
30.06"Hg - Average pressure in April:
29.95"Hg - Average pressure in May:
29.91"Hg - Average pressure in June:
29.9"Hg
- Average pressure in July:
29.96"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
29.98"Hg - Average pressure in October:
30.05"Hg - Average pressure in November:
30.14"Hg - Average pressure in December:
30.24"Hg
The month with the highest atmospheric pressure is January (30.27"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed
Boulder, WY
- Average wind speed in January:
6.1mph - Average wind speed in February:
6.5mph - Average wind speed in March:
6.5mph - Average wind speed in April:
7.9mph - Average wind speed in May:
7.8mph - Average wind speed in June:
8.1mph
- Average wind speed in July:
6.8mph - Average wind speed in August:
6.5mph - Average wind speed in September:
6.6mph - Average wind speed in October:
6.9mph - Average wind speed in November:
6.3mph - Average wind speed in December:
5.8mph
The windiest month (with the highest average wind speed) is June (8.1mph).
The calmest month (with the lowest average wind speed) is December (5.8mph).
Average humidity
Boulder, WY
The month with the highest relative humidity is February (86%).
The month with the lowest relative humidity is August (34%).
Average rainfall
Boulder, WY
- Average rainfall in January:
0.63" - Average rainfall in February:
0.94" - Average rainfall in March:
0.98" - Average rainfall in April:
1.61" - Average rainfall in May:
1.73" - Average rainfall in June:
0.91"
- Average rainfall in July:
0.55" - Average rainfall in August:
0.51" - Average rainfall in September:
0.79" - Average rainfall in October:
0.83" - Average rainfall in November:
0.71" - Average rainfall in December:
0.55"
The wettest month (with the highest rainfall) is May (1.73").
The driest month (with the least rainfall) is August (0.51").
Average rainfall days
Boulder, WY
- Average rainfall days in January:
5.5 days - Average rainfall days in February:
7.9 days - Average rainfall days in March:
9.6 days - Average rainfall days in April:
12.2 days - Average rainfall days in May:
15.2 days - Average rainfall days in June:
9.9 days
- Average rainfall days in July:
7.8 days - Average rainfall days in August:
7.1 days - Average rainfall days in September:
7.2 days - Average rainfall days in October:
7.2 days - Average rainfall days in November:
5.8 days - Average rainfall days in December:
7.2 days
The month with the highest number of rainy days is May (15.2 days).
The month with the least rainy days is January (5.5 days).
Average snowfall
Boulder, WY
- Average snowfall in January:
5.08" - Average snowfall in February:
7.32" - Average snowfall in March:
7.05" - Average snowfall in April:
6.97" - Average snowfall in May:
2.36" - Average snowfall in June:
0.67"
The month with the highest snowfall is February (7.32").
The months with the least snowfall are July and August (0").
Average snowfall days
Boulder, WY
- Average snowfall days in January:
10.2 days - Average snowfall days in February:
14.7 days - Average snowfall days in March:
15.7 days - Average snowfall days in April:
11.6 days - Average snowfall days in May:
4.3 days - Average snowfall days in June:
0.8 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0.6 days - Average snowfall days in October:
5.5 days - Average snowfall days in November:
9.9 days - Average snowfall days in December:
13.5 days
The month with the highest number of snowfall days is March (15.7 days).
The months with the least snowfall days are July and August (0 days).
Average daylight / Average sunshine
Boulder, WY
- Average daylight in January:
9h and 30min - Average daylight in February:
10h and 36min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 24min - Average daylight in May:
14h and 42min - Average daylight in June:
15h and 18min
- Average daylight in July:
15h and 0min - Average daylight in August:
13h and 54min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 0min - Average daylight in November:
9h and 48min - Average daylight in December:
9h and 6min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in January:
6h and 18min - Average sunshine in February:
6h and 24min - Average sunshine in March:
8h and 6min - Average sunshine in April:
10h and 18min - Average sunshine in May:
11h and 6min - Average sunshine in June:
11h and 48min
- Average sunshine in July:
11h and 54min - Average sunshine in August:
11h and 54min - Average sunshine in September:
10h and 42min - Average sunshine in October:
7h and 12min - Average sunshine in November:
7h and 0min - Average sunshine in December:
6h and 30min
The months with the most sunshine are July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 6h and 18min).
Average sunshine days
Boulder, WY
- Average sunshine days in January:
19.8 days - Average sunshine days in February:
12.3 days - Average sunshine days in March:
12.4 days - Average sunshine days in April:
9.9 days - Average sunshine days in May:
9.7 days - Average sunshine days in June:
16.4 days
- Average sunshine days in July:
18.6 days - Average sunshine days in August:
18.7 days - Average sunshine days in September:
18.5 days - Average sunshine days in October:
19.6 days - Average sunshine days in November:
19 days - Average sunshine days in December:
16.7 days
The month with the most sunshine days is January (19.8 days).
The month with the least sunshine days is May (9.7 days).
Average UV index
Boulder, WY
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).
Average cloud cover
Boulder, WY
The month with the most cloud cover is February (Cloud cover 39).
The month with the least cloud cover is August (Cloud cover 11).
Average visibility
Boulder, WY
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and February (4mi).
