The highest day temperature in May 2026 was 84°F. The lowest night temperature was 24°F. The average values for day and night temperatures during May were 66.2°F и 43.5°F respectivly.

You can expect various weather conditions during May. Be ready for sunny, cloudy or even gloomy days.

Precipitation total in May for Boulder is 2.4 in. It makes may the most rainy month of the year.

The average wind speed in May is 6.9 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Boulder in May is 8.3 hours.