Sunrise and Sunset times in Boulder, United States 
Boulder
Colorado
Time zone: America/Denver, UTC -6 h.
Latitude: 40.0249, Longitude: -105.252
126 054 people
| Date | Sunrise | Solar Noon | Sunset | Length of day |
|---|---|---|---|---|
| 2025-Jun-01, Sunday | 05:33:49 | 12:58:57 | 20:24:04 | 14h 50m 15s |
| 2025-Jun-02, Monday | 05:33:27 | 12:59:07 | 20:24:46 | 14h 51m 19s |
| 2025-Jun-03, Tuesday | 05:33:06 | 12:59:17 | 20:25:27 | 14h 52m 21s |
| 2025-Jun-04, Wednesday | 05:32:47 | 12:59:27 | 20:26:07 | 14h 53m 20s |
| 2025-Jun-05, Thursday | 05:32:30 | 12:59:38 | 20:26:45 | 14h 54m 15s |
| 2025-Jun-06, Friday | 05:32:15 | 12:59:49 | 20:27:22 | 14h 55m 7s |
| 2025-Jun-07, Saturday | 05:32:02 | 13:00:00 | 20:27:58 | 14h 55m 56s |
| 2025-Jun-08, Sunday | 05:31:51 | 13:00:12 | 20:28:32 | 14h 56m 41s |
| 2025-Jun-09, Monday | 05:31:42 | 13:00:23 | 20:29:04 | 14h 57m 22s |
| 2025-Jun-10, Tuesday | 05:31:35 | 13:00:35 | 20:29:36 | 14h 58m 1s |
| 2025-Jun-11, Wednesday | 05:31:30 | 13:00:48 | 20:30:05 | 14h 58m 35s |
| 2025-Jun-12, Thursday | 05:31:27 | 13:01:00 | 20:30:34 | 14h 59m 7s |
| 2025-Jun-13, Friday | 05:31:25 | 13:01:13 | 20:31:00 | 14h 59m 35s |
| 2025-Jun-14, Saturday | 05:31:26 | 13:01:25 | 20:31:25 | 14h 59m 59s |
| 2025-Jun-15, Sunday | 05:31:28 | 13:01:38 | 20:31:48 | 15h 0m 20s |
| 2025-Jun-16, Monday | 05:31:32 | 13:01:51 | 20:32:10 | 15h 0m 38s |
| 2025-Jun-17, Tuesday | 05:31:39 | 13:02:04 | 20:32:30 | 15h 0m 51s |
| 2025-Jun-18, Wednesday | 05:31:47 | 13:02:17 | 20:32:48 | 15h 1m 1s |
| 2025-Jun-19, Thursday | 05:31:56 | 13:02:30 | 20:33:04 | 15h 1m 8s |
| 2025-Jun-20, Friday | 05:32:08 | 13:02:43 | 20:33:19 | 15h 1m 11s |
| 2025-Jun-21, Saturday | 05:32:22 | 13:02:57 | 20:33:32 | 15h 1m 10s |
| 2025-Jun-22, Sunday | 05:32:37 | 13:03:10 | 20:33:42 | 15h 1m 5s |
| 2025-Jun-23, Monday | 05:32:54 | 13:03:22 | 20:33:51 | 15h 0m 57s |
| 2025-Jun-24, Tuesday | 05:33:12 | 13:03:35 | 20:33:59 | 15h 0m 47s |
| 2025-Jun-25, Wednesday | 05:33:32 | 13:03:48 | 20:34:04 | 15h 0m 32s |
| 2025-Jun-26, Thursday | 05:33:54 | 13:04:01 | 20:34:07 | 15h 0m 13s |
| 2025-Jun-27, Friday | 05:34:18 | 13:04:13 | 20:34:08 | 14h 59m 50s |
| 2025-Jun-28, Saturday | 05:34:43 | 13:04:25 | 20:34:08 | 14h 59m 25s |
| 2025-Jun-29, Sunday | 05:35:09 | 13:04:37 | 20:34:05 | 14h 58m 56s |
| 2025-Jun-30, Monday | 05:35:38 | 13:04:49 | 20:34:00 | 14h 58m 22s |
Boulder on United States map:
Cities in the same time zone America/Denver
Denver (Colorado), Salt Lake City (Utah), El Paso (Texas), Albuquerque (New Mexico), Colorado Springs (Colorado), Ogden (Utah), Provo (Utah), Aurora (Colorado), Fort Collins (Colorado), Lakewood (Colorado), Pueblo (Colorado), Thornton (Colorado), Grand Junction (Colorado), West Valley City (Utah), Las Cruces (New Mexico), Greeley (Colorado), Billings (Montana), Arvada (Colorado), St. George (Utah), West Jordan (Utah), Westminster (Colorado), Centennial (Colorado), Santa Fe (New Mexico), Highlands Ranch (Colorado), Logan (Utah), Longmont (Colorado), Orem (Utah), Rio Rancho (New Mexico), Sandy (Utah), Lafayette (Colorado)
Largest Populated Areas in United States
New York (New York), Los Angeles (California), Chicago (Illinois), Miami (Florida), Dallas (Texas), Philadelphia (Pennsylvania), Houston (Texas), Washington (District of Columbia), Atlanta (Georgia), Boston (Massachusetts), Phoenix (Arizona), Seattle (Washington), San Francisco (California), Detroit (Michigan), San Diego (California), Minneapolis (Minnesota), Tampa (Florida), Denver (Colorado), Brooklyn (New York), Queens (New York), Baltimore (Maryland), Riverside (California), St. Louis (Missouri), Las Vegas (Nevada), Portland (Oregon), San Antonio (Texas), Sacramento (California), San Jose (California), Orlando (Florida), Cleveland (Ohio)
Daylight Hours FAQ: 10 Most Googled Questions Answered
1. What are daylight hours?
Daylight hours refer to the period between sunrise and sunset. This duration changes throughout the year based on season and geographic location.
2. Why are days shorter in winter and longer in summer?
Earth's 23.5° axial tilt causes uneven sunlight distribution. Your hemisphere receives less direct sunlight in winter (shorter days) and more in summer (longer days).
3. When is the longest day of the year?
Northern Hemisphere: June 20-22 (summer solstice).
Southern Hemisphere: December 21-23.
Near polar circles, the sun doesn't set for 24 hours.
4. When is the shortest day of the year?
Northern Hemisphere: December 21-22 (winter solstice).
Southern Hemisphere: June 20-21.
5. How does latitude affect daylight hours?
The closer to poles, the more extreme variations:
- Equator: ~12-hour days year-round
- Polar regions: Midnight sun/polar nights occur
6. Why do New York and Miami have different day lengths?
Miami's lower latitude means:
- Winter days are longer than NY's
- Summer days are slightly shorter
7. When are day and night equal?
During equinoxes:
- Spring: March 20-21
- Fall: September 22-23
How fast do days lengthen/shorten?
Most rapid change near equinoxes: 2-4 minutes daily.
Slowest change near solstices: <1 minute daily.
9. Where can I check daylight hours for my city?
Reliable tools:
- Timeanddate.com
- SunCalc.org
- Photographer's Ephemeris app
10. Does daylight affect health?
Yes. Reduced winter sunlight may cause:
- Seasonal Affective Disorder (SAD)
- Vitamin D deficiency
Solution: Light therapy lamps & midday walks