This report describes the typical weather at the Boulder Municipal Airport (Boulder, Colorado, United States) weather station over the course of an average April 22. It is based on the historical records from 2010 to 2013. Earlier records are either unavailable or unreliable.
Boulder, Colorado has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by grasslands (40%), forests (32%), shrublands (18%), built-up areas (8%), and croplands (3%).
The temperature typically varies from 43°F to 61°F and is rarely below 38°F or above 69°F.
The coolest hours of the day are from 2am to 8am with the coldest at 5am, at which time the temperature is below 47°F three days out of four.
The warmest hours of the day are from noon to 7pm with the hottest at 4pm, at which time the temperature is above 55°F three days out of four.
The day has gained half its heat by 10am and lost it again by 10pm.
On April 22 the Sun rises at 6:12am and sets at 7:47pm.
Solar noon is at 12:59pm.
For reference, on the longest day of the year the Sun rises at 5:32am and sets at 8:32pm, while on the shortest day of the year it rises at 7:19am and sets at 4:39pm.
Astronomical twilight begins and ends 99 minutes before sunrise and after sunset at 4:33am and 9:26pm, respectively.
Nautical twilight begins and ends 63 minutes before sunrise and after sunset at 5:09am and 8:50pm, respectively.
Civil twilight begins and ends 29 minutes before sunrise and after sunset at 5:43am and 8:15pm, respectively.
Solar twilight begins and ends 36 minutes after sunrise and before sunset at 6:49am and 7:10pm, respectively.
The median cloud cover is 28% (mostly clear) and does not vary substantially over the course of the day.
On average, the sky is clear or mostly clear 61% of the time, partly cloudy 10% of the time, and mostly cloudy or overcast 29% of the time.
There is either very little precipitation at this location on April 22, or the weather station does not reliably report the conditions.
Either snow is exceptionally unlikely to fall at this location on April 22 or this station does not reliably report precipitation types.
The relative humidity typically ranges from 32% (comfortable) to 61% (mildly humid), rarely dropping below 19% (dry), or exceeding 76% (humid).
The air is driest at 4pm, at which time the relative humidity is less than 40% (comfortable) three days out of four; it is most humid at 5am, exceeding 52% (mildly humid) three days out of four.
The dew point ranges from 25°F to 30°F with an average of 28°F.
For reference, comfortable indoor conditions should have a relative humidity between 30% and 50% with a dew point of less than 65°F.
Sustained wind speeds typically vary from 3 mph to 10 mph (light air to gentle breeze) over the course of the day.
The peak sustained wind speed typically occurs around 4pm and is rarely outside the range 5 mph to 15 mph (light breeze to moderate breeze).
The wind is most calm around 5am, rarely exceeding 6 mph (light breeze).
The wind is most often out of the west (17% of the time), north (15% of the time), south west (12% of the time), east (12% of the time), and north east (11% of the time).