The best times to visit Boulder for ideal weather are
May 14th to September 30th
based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.
Boulder Travel Guide
Other Boulder Travel Info
Weather in Boulder
Average temperatures in Boulder vary drastically. Considering humidity, temperatures feel cold for about half of the year and otherwise nice with a very low chance of rain or snow throughout the year. The area is somewhat temperate — in the 48th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Boulder, the hottest months are July, August, and then June. See average monthly temperatures below. The warmest time of year is generally late June where highs are regularly around 93.9°F (34.4°C) with temperatures rarely dropping below 57.9°F (14.4°C) at night.
Boulder Temperatures (Fahrenheit)
Boulder Temperatures (Celsius)
The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.
Boulder Perceived Temperature (F)
Boulder Perceived Temperature (C)
Average Boulder Temperatures by Month
Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.
|Month||Avg. High (°F)||Avg. Mean (°F)||Avg. Low (°F)|
|Month||Avg. High (°C)||Avg. Mean (°C)||Avg. Low (°C)|
Precipitation (Rain or Snow)
If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Boulder are March, April, and then June. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around early January. For example, on the week of January 1st there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in early to mid May with an average of 1 days of significant precipitation the week of May 7th.
When can you find snow in Boulder? Weather stations report no annual snow. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.
Chance of Precipitation
The graph below shows the % chance of rainy and snowy days in Boulder.
Snow on the Ground
The graph below shows the average snow on the ground in Boulder (in).
Average Rain and Snow by Month
|Month||Daily Chance of Rain||Average Snow Depth (in)||Total Precipitation (in)|
|Month||Daily Chance of Rain||Average Snow Depth (cm)||Total Precipitation (cm)|
Humidity and Wind
Boulder has some comfortably humid months, and slightly dry months in the opposite season. The least humid month is March (31.3% relative humidity), and the most humid month is December (46.4%).
Wind in Boulder is usually calm. The windiest month is April, followed by March and February. April’s average wind speed of around 5.3 knots (6.1 MPH or 9.9 KPH) is considered “a light breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in mid February where average top sustained speeds reach 17.4 knots, which is considered a fresh breeze.
Relative Humidity (%)
The graph below shows the average % humidity by month in Boulder.
The graph below shows wind speed (max and average) in knots.
Average Wind Speeds
Show Wind Speeds
All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.
|Month||Avg. Wind||Avg. Wind Feel||Sustained High Wind||High Wind Feel|
|Jan||3.9||Barely noticeable||13.3||Significant breeze|
|Feb||4.7||Light breeze||14.5||Significant breeze|
|Mar||5.1||Light breeze||15.8||Significant breeze|
|Apr||5.3||Light breeze||15.6||Significant breeze|
|May||4.1||Light breeze||13.7||Significant breeze|
|Jun||4.1||Light breeze||14||Significant breeze|
|Jul||3.6||Barely noticeable||13.6||Significant breeze|
|Aug||3.3||Barely noticeable||12.6||Significant breeze|
|Sep||3||Barely noticeable||11.1||Significant breeze|
|Oct||3.3||Barely noticeable||11.1||Significant breeze|
|Nov||4||Light breeze||12.3||Significant breeze|
|Dec||3.5||Barely noticeable||11.2||Significant breeze|
Show Relative Humidity by Month
|Month||Avg. Relative Humidity|
Is it Safe to Travel to Boulder?
Our best data indicates this area is generally safe. As of Oct 07, 2019 there are no travel advisories or warnings for the United States; exercise normal security precautions. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Sep 23, 2019.
The Busiest and Least Crowded Months
The busiest month for tourism in Boulder, CO, US is August, followed by September and May. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Boulder in October. Those willing to visit at these times will likely find it the least expensive month.
Estimated Tourism by Month
Most Popular Months to Visit
Overall Boulder Travel Experience by Season
Spring (March through May)
Humidity and temperatures combine to make this season feel moderately cold. Highs range from 83.3°F (28.5°C) and 48.9°F (9.4°C) with warmer temperatures in the later months. Rain is extremely rare with 0 to 2 days of significant precipitation per month. Spring is fairly slow for tourism, which makes it a good time for those looking for deals.
Summer (June through August)
The middle-year months have very comfortable weather with high temperatures that are quite warm. These months see the least precipitation with 0 to 1 days of precipitation per month. June – August is the busiest season for tourism in Boulder, so lodging and other accommodations may cost more than usual.
Fall (September through November)
Fall daily highs range from 84.1°F (28.9°C) and 51°F (10.6°C), which will feel chilly given the humidity and wind. It rains or snows a normal amount: 0 to 2 days per month. Tourism is the slowest during these months due to the weather, so hotels may be affordably priced.
Winter (December through February)
Weather is far too cold this time of year in Boulder to be enjoyable for warm weather travelers. The average high during this season is between 54.2°F (12.3°C) and 40.3°F (4.6°C). On average, it rains or snows a very small amount: 0 to 1 times per month. These times of year are the second busiest with tourists.