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United States weather

Weather in Boulder County, Colorado for May 2026

Your guide to Boulder County weather in May - trends and predictions

    Temperatures

  • Until now, May 2026 in Boulder County has been nearly identical to the historical average, with a temperature of 15.8 °F (showing only a slight deviation of 0.3 °F).

  • The forecast for the next days in Boulder County predicts the temperature to be 28 °F, significantly warmer than the historical average.

  • In general, the average temperature in Boulder County at the beginning of May is 15 °F. As the month progressed, temperatures tended to significantly warm up, reaching an average of 19.6 °F by the end of May.

    • Rain 🌧️

  • Boulder County in May brings notable rainfall, with an average of 16 rainy days and a total precipitation of 177.1 mm.

    • More

  • New! Chat with our AI weatherman - it’s amazing and free.

Average dry days
15
Dry days
Average rainy days
16
Rainy days
Average snowy days
0
Snow days
Average temperatures
18°/6°
Temperatures
Average wind speed
21 km/h
Avg max wind
Average humidity
53 %
Avg humidity

Boulder County Weather May

Move between months or click on a day
April
June
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
1
Overcast
13°
2
Sunny
17°
3
Patchy rain possible
20°
4
Overcast
20°
5
Overcast
14°
6
Patchy rain possible
8°
7
Patchy rain possible
13°
8
Cloudy
16°
9
Overcast
18°
10
Moderate rain at times
18°
11
Sunny
29°
12
Sunny
24°
13
Patchy rain possible
28°
14
Patchy rain possible
25°
15
Sunny
28°
16
Sunny
27°
17
Sunny
28°
18
Sunny
28°
19
Partly cloudy
29°
20
Sunny
30°
21
Sunny
25°
22
Sunny
31°
23
Patchy rain possible
29°
24
Sunny
31°
25
Heavy rain at times
16°
26
Sunny
15°
27
Sunny
20°
28
Cloudy
19°
29
Cloudy
21°
30
Overcast
23°
31
Patchy light drizzle
23°

Temperatures trend during May in Boulder County

See the weather trend as well as the moving average line

May weather in Boulder County day by day

Click on a date for more information
April June
Date Weather Temperatures Rain Snow More
May 1 Overcast
Overcast
 13° /2° 1.4 mm 0 cm
May 2 Sunny
Sunny
 17° /1° 0.1 mm 0 cm
May 3 Patchy rain possible
Patchy rain possible
 20° /3° 0.1 mm 0 cm
May 4 Overcast
Overcast
 20° /6° 0.7 mm 0 cm
May 5 Overcast
Overcast
 14° /3° 17.2 mm 0 cm
May 6 Patchy rain possible
Patchy rain possible
 8° /0° 36.8 mm 1.1 cm
May 7 Patchy rain possible
Patchy rain possible
 13° /-1° 17.8 mm 0 cm
May 8 Cloudy
Cloudy
 16° /2° 0 mm 0 cm
May 9 Overcast
Overcast
 18° /5° 0.9 mm 0 cm
May 10 Moderate rain at times
Moderate rain at times
 18° /4° 0.7 mm 0 cm
May 11 Sunny
Sunny
 29° /7° 0 mm 0 cm
May 12 Sunny
Sunny
 24° /9° 0 mm 0 cm
May 13 Patchy rain possible
Patchy rain possible
 28° /10° 1.1 mm 0 cm
May 14 Patchy rain possible
Patchy rain possible
 25° /12° 0.5 mm 0 cm
May 15 Sunny
Sunny
 28° /10° 0 mm 0 cm
May 16 Sunny
Sunny
 27° /7° 0 mm 0 cm
May 17 Sunny
Sunny
 28° /7° 0 mm 0 cm
May 18 Sunny
Sunny
 28° /11° 0.1 mm 0 cm
May 19 Partly cloudy
Partly cloudy
 29° /10° 0 mm 0 cm
May 20 Sunny
Sunny
 30° /10° 0 mm 0 cm
May 21 Sunny
Sunny
 25° /10° 0 mm 0 cm
May 22 Sunny
Sunny
 31° /8° 0 mm 0 cm
May 23 Patchy rain possible
Patchy rain possible
 29° /12° 0.4 mm 0 cm
May 24 Sunny
Sunny
 31° /13° 0 mm 0 cm
May 25 Heavy rain at times
Heavy rain at times
 16° /6° 35.5 mm 0 cm
May 26 Sunny
Sunny
 15° /6° 9.9 mm 0 cm
May 27 Sunny
Sunny
 20° /8° 1.7 mm 0 cm
May 28 Cloudy
Cloudy
 19° /8° 0 mm 0 cm
May 29 Cloudy
Cloudy
 21° /7° 2.2 mm 0 cm
May 30 Overcast
Overcast
 23° /9° 5.3 mm 0 cm
May 31 Patchy light drizzle
Patchy light drizzle
 23° /8° 0.5 mm 0 cm
Next
Important Notice
Our weather forecast for Boulder County in May is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Boulder County forecast closer to your planned date for the most up-to-date weather information.
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Boulder County in May - FAQ

What are the expected maximum and minimum temperatures in Boulder County during May?

Enjoy moderate daytime temperatures of up to 18° and cooler nights around 6°. Ideal for a range of outdoor activities, from hiking to city tours.

How much rainfall should be expected in Boulder County during May?

Significant rainfall exceeding 177.1 mm is expected in Boulder County during May, occurring over more than 16 days. Preparing for wet conditions is recommended in your planning.

What are the typical wind conditions in Boulder County during May?

The average wind speed in Boulder County during May is 21 km/h, suggesting breezy to windy conditions, depending on your activities.

Boulder County snow forecast May 2026

Track daily snowfall levels and discover Boulder County’s snowy potential this May ❄️

May rainfall patterns in Boulder County

Explore the daily rainfall trends and prepare for Boulder Countys May weather 💧
Typically, Boulder County has 16 rainy days in May with a total of 177.1 mm of rainfall.

UV exposure in Boulder County during May

Stay informed about UV levels for safe outdoor activities throughout the month of May ☀️
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Location coordinates Where is Boulder County?

Get accurate weather forecasts for Boulder County, located at latitude 40.015 and longitude -105.271. Stay updated with localized weather information tailored for Boulder County.

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