Boulder, Colorado, United States - Sunrise, sunset, dawn and dusk times, table

Date Sunrise Sunset Length Change Dawn Dusk Length Change
Today 07:17 18:14 10:57   06:50 18:41 11:51  
+1 day 07:18 18:13 10:55 00:02 shorter 06:51 18:40 11:49 00:02 shorter
+1 week 07:25 18:05 10:40 00:17 shorter 06:57 18:32 11:35 00:16 shorter
+2 weeks 06:33 16:56 10:23 00:34 shorter 06:04 17:24 11:20 00:31 shorter
+1 month 06:51 16:42 9:51 01:06 shorter 06:22 17:11 10:49 01:02 shorter
+2 months 07:18 16:38 9:20 01:37 shorter 06:48 17:09 10:21 01:30 shorter
+3 months 07:20 17:04 9:44 01:13 shorter 06:50 17:33 10:43 01:08 shorter
+6 months 06:16 19:45 13:29 02:32 longer 05:48 20:13 14:25 02:34 longer
Notes: Daylight saving time, * = Next day. Change preferences.

Boulder, Colorado, United States - Sunrise, sunset, dawn and dusk times, graph

Whole year sunrise, sunset, dawn and dusk times graph Sunrise, sunset, dawn and dusk times for the whole year in a graph requires SVG, so it cannot work on your current browser with its current settings. Sorry. A PNG version of this graph is also available. 23:00 22:00 21:00 20:00 19:00 18:00 17:00 16:00 15:00 14:00 13:00 11:00 10:00 09:00 08:00 07:00 06:00 05:00 04:00 03:00 02:00 01:00 12:00 January February March April May June July August September October November December Today 2323:00 2222:00 2121:00 2020:00 1919:00 1818:00 1717:00 1616:00 1515:00 1414:00 1313:00 1212:00 1111:00 1010:00 909:00 808:00 707:00 606:00 505:00 404:00 303:00 202:00 101:00 IJanuary IIFebruary IIIMarch IVApril VMay VIJune VIIJuly VIIIAugust IXSeptember XOctober XINovember XIIDecember © Gaisma.com 216.73.217.172, 2026-10-20T08:08
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Boulder, Colorado, United States - Sun path diagram

Sun path diagram Sun path diagram requires SVG, so it cannot work on your current browser with its current settings. Sorry. PNG version of sun path diagram graph is also available. Annual variation Horizon 80° 70° 60° 50° 40° 30° 20° 10° 0° 30° 60° 90° 120° 150° 180° 210° 240° 270° 300° 330° 80° 70° 60° 50° 40° 30° 20° 10° N 30 60 E 120 150 S 210 240 W 300 330 UVA, Vertical cylinder UVB, Vertical cylinder UVA, Horizontal plane UVB, Horizontal plane UVB radiation is sufficient for vitamin D3 synthesis Shadow length Sun path, June solstice Time: 05:00, Azimuth: 52°, Elevation: -5° Time: 05:32, Azimuth: 57°, Elevation: 0° Time: 06:00, Azimuth: 62°, Elevation: 3° Time: 07:00, Azimuth: 71°, Elevation: 14° Time: 08:00, Azimuth: 79°, Elevation: 25° Time: 09:00, Azimuth: 88°, Elevation: 36° Time: 10:00, Azimuth: 99°, Elevation: 48° Time: 11:00, Azimuth: 113°, Elevation: 59° Time: 12:00, Azimuth: 136°, Elevation: 68° Time: 13:00, Azimuth: 177°, Elevation: 73° Time: 14:00, Azimuth: 220°, Elevation: 69° Time: 15:00, Azimuth: 244°, Elevation: 60° Time: 16:00, Azimuth: 259°, Elevation: 49° Time: 17:00, Azimuth: 270°, Elevation: 37° Time: 18:00, Azimuth: 279°, Elevation: 26° Time: 19:00, Azimuth: 287°, Elevation: 15° Time: 20:00, Azimuth: 296°, Elevation: 4° Time: 20:34, Azimuth: 302°, Elevation: 0° Time: 21:00, Azimuth: 306°, Elevation: -4° Time: 22:00, Azimuth: 317°, Elevation: -13° Time: 04:00, Azimuth: 41°, Elevation: -14° 05:32 06 09 12 15 18 20:34 Sun path, December solstice Time: 07:00, Azimuth: 117°, Elevation: -4° Time: 07:20, Azimuth: 120°, Elevation: 0° Time: 08:00, Azimuth: 127°, Elevation: 5° Time: 09:00, Azimuth: 138°, Elevation: 14° Time: 10:00, Azimuth: 150°, Elevation: 20° Time: 11:00, Azimuth: 164°, Elevation: 25° Time: 12:00, Azimuth: 180°, Elevation: 26° Time: 13:00, Azimuth: 195°, Elevation: 25° Time: 14:00, Azimuth: 209°, Elevation: 20° Time: 15:00, Azimuth: 222°, Elevation: 13° Time: 16:00, Azimuth: 233°, Elevation: 5° Time: 16:39, Azimuth: 239°, Elevation: 0° Time: 17:00, Azimuth: 242°, Elevation: -4° Time: 18:00, Azimuth: 251°, Elevation: -14° Time: 06:00, Azimuth: 108°, Elevation: -14° 07:20 09 12 15 16:39 Sun path, Equinox (March and September) Sun path, January Time: 07:00, Azimuth: 112°, Elevation: -3° Time: 07:18, Azimuth: 115°, Elevation: 0° Time: 08:00, Azimuth: 122°, Elevation: 6° Time: 09:00, Azimuth: 133°, Elevation: 15° Time: 10:00, Azimuth: 146°, Elevation: 22° Time: 11:00, Azimuth: 160°, Elevation: 27° Time: 12:00, Azimuth: 176°, Elevation: 30° Time: 13:00, Azimuth: 192°, Elevation: 29° Time: 14:00, Azimuth: 208°, Elevation: 25° Time: 15:00, Azimuth: 221°, Elevation: 18° Time: 16:00, Azimuth: 233°, Elevation: 10° Time: 17:00, Azimuth: 243°, Elevation: 0° Time: 17:07, Azimuth: 244°, Elevation: 0° Time: 18:00, Azimuth: 252°, Elevation: -10° Time: 06:00, Azimuth: 103°, Elevation: -14° 07:18 09 12 15 17:07 Sun path, February Time: 06:00, Azimuth: 95°, Elevation: -9° Time: 06:46, Azimuth: 102°, Elevation: 0° Time: 07:00, Azimuth: 105°, Elevation: 2° Time: 08:00, Azimuth: 115°, Elevation: 12° Time: 09:00, Azimuth: 126°, Elevation: 22° Time: 10:00, Azimuth: 140°, Elevation: 30° Time: 11:00, Azimuth: 156°, Elevation: 36° Time: 12:00, Azimuth: 175°, Elevation: 39° Time: 13:00, Azimuth: 194°, Elevation: 38° Time: 14:00, Azimuth: 211°, Elevation: 34° Time: 15:00, Azimuth: 226°, Elevation: 26° Time: 16:00, Azimuth: 239°, Elevation: 17° Time: 17:00, Azimuth: 250°, Elevation: 7° Time: 17:44, Azimuth: 257°, Elevation: 0° Time: 18:00, Azimuth: 259°, Elevation: -3° Time: 19:00, Azimuth: 269°, Elevation: -15° 06:46 09 12 15 17:44 Sun path, March Time: 07:00, Azimuth: 88°, Elevation: -1° Time: 07:04, Azimuth: 89°, Elevation: 0° Time: 08:00, Azimuth: 98°, Elevation: 9° Time: 09:00, Azimuth: 108°, Elevation: 21° Time: 10:00, Azimuth: 120°, Elevation: 31° Time: 11:00, Azimuth: 135°, Elevation: 40° Time: 12:00, Azimuth: 154°, Elevation: 47° Time: 13:00, Azimuth: 176°, Elevation: 50° Time: 14:00, Azimuth: 199°, Elevation: 48° Time: 15:00, Azimuth: 219°, Elevation: 42° Time: 16:00, Azimuth: 235°, Elevation: 34° Time: 17:00, Azimuth: 248°, Elevation: 24° Time: 18:00, Azimuth: 258°, Elevation: 13° Time: 19:00, Azimuth: 268°, Elevation: 2° Time: 19:13, Azimuth: 270°, Elevation: 0° Time: 20:00, Azimuth: 278°, Elevation: -9° Time: 06:00, Azimuth: 78°, Elevation: -12° 07:04 09 12 15 18 19:13 Sun path, April Time: 06:00, Azimuth: 71°, Elevation: -3° Time: 06:14, Azimuth: 73°, Elevation: 0° Time: 07:00, Azimuth: 80°, Elevation: 7° Time: 08:00, Azimuth: 90°, Elevation: 19° Time: 09:00, Azimuth: 100°, Elevation: 30° Time: 10:00, Azimuth: 112°, Elevation: 41° Time: 11:00, Azimuth: 128°, Elevation: 51° Time: 12:00, Azimuth: 150°, Elevation: 59° Time: 13:00, Azimuth: 180°, Elevation: 62° Time: 14:00, Azimuth: 209°, Elevation: 59° Time: 15:00, Azimuth: 231°, Elevation: 51° Time: 16:00, Azimuth: 247°, Elevation: 41° Time: 17:00, Azimuth: 259°, Elevation: 30° Time: 18:00, Azimuth: 269°, Elevation: 19° Time: 19:00, Azimuth: 279°, Elevation: 7° Time: 19:46, Azimuth: 286°, Elevation: 0° Time: 20:00, Azimuth: 288°, Elevation: -3° Time: 21:00, Azimuth: 299°, Elevation: -13° Time: 05:00, Azimuth: 60°, Elevation: -13° 06:14 09 12 15 18 19:46 Sun path, May Time: 05:00, Azimuth: 55°, Elevation: -7° Time: 05:41, Azimuth: 62°, Elevation: 0° Time: 06:00, Azimuth: 65°, Elevation: 2° Time: 07:00, Azimuth: 74°, Elevation: 13° Time: 08:00, Azimuth: 83°, Elevation: 24° Time: 09:00, Azimuth: 92°, Elevation: 36° Time: 10:00, Azimuth: 104°, Elevation: 47° Time: 11:00, Azimuth: 119°, Elevation: 58° Time: 12:00, Azimuth: 143°, Elevation: 66° Time: 13:00, Azimuth: 181°, Elevation: 70° Time: 14:00, Azimuth: 218°, Elevation: 66° Time: 15:00, Azimuth: 242°, Elevation: 57° Time: 16:00, Azimuth: 256°, Elevation: 46° Time: 17:00, Azimuth: 267°, Elevation: 35° Time: 18:00, Azimuth: 277°, Elevation: 23° Time: 19:00, Azimuth: 286°, Elevation: 12° Time: 20:00, Azimuth: 295°, Elevation: 2° Time: 20:15, Azimuth: 297°, Elevation: 0° Time: 21:00, Azimuth: 305°, Elevation: -8° Time: 22:00, Azimuth: 316°, Elevation: -16° Time: 04:00, Azimuth: 44°, Elevation: -16° 05:41 06 09 12 15 18 20:15 Sun path, July Time: 05:00, Azimuth: 53°, Elevation: -8° Time: 05:50, Azimuth: 62°, Elevation: 0° Time: 06:00, Azimuth: 63°, Elevation: 1° Time: 07:00, Azimuth: 72°, Elevation: 11° Time: 08:00, Azimuth: 81°, Elevation: 22° Time: 09:00, Azimuth: 91°, Elevation: 34° Time: 10:00, Azimuth: 101°, Elevation: 45° Time: 11:00, Azimuth: 116°, Elevation: 56° Time: 12:00, Azimuth: 138°, Elevation: 65° Time: 13:00, Azimuth: 174°, Elevation: 70° Time: 14:00, Azimuth: 213°, Elevation: 67° Time: 15:00, Azimuth: 238°, Elevation: 58° Time: 16:00, Azimuth: 254°, Elevation: 48° Time: 17:00, Azimuth: 266°, Elevation: 37° Time: 18:00, Azimuth: 275°, Elevation: 25° Time: 19:00, Azimuth: 284°, Elevation: 14° Time: 20:00, Azimuth: 293°, Elevation: 3° Time: 20:25, Azimuth: 297°, Elevation: 0° Time: 21:00, Azimuth: 303°, Elevation: -6° Time: 22:00, Azimuth: 314°, Elevation: -15° Time: 04:00, Azimuth: 42°, Elevation: -17° 05:50 06 09 12 15 18 20:25 Sun path, August Time: 06:00, Azimuth: 70°, Elevation: -4° Time: 06:19, Azimuth: 73°, Elevation: 0° Time: 07:00, Azimuth: 80°, Elevation: 7° Time: 08:00, Azimuth: 89°, Elevation: 18° Time: 09:00, Azimuth: 99°, Elevation: 29° Time: 10:00, Azimuth: 111°, Elevation: 40° Time: 11:00, Azimuth: 127°, Elevation: 50° Time: 12:00, Azimuth: 148°, Elevation: 58° Time: 13:00, Azimuth: 177°, Elevation: 61° Time: 14:00, Azimuth: 207°, Elevation: 59° Time: 15:00, Azimuth: 230°, Elevation: 52° Time: 16:00, Azimuth: 246°, Elevation: 42° Time: 17:00, Azimuth: 258°, Elevation: 31° Time: 18:00, Azimuth: 268°, Elevation: 19° Time: 19:00, Azimuth: 278°, Elevation: 8° Time: 19:49, Azimuth: 286°, Elevation: 0° Time: 20:00, Azimuth: 288°, Elevation: -2° Time: 21:00, Azimuth: 298°, Elevation: -13° Time: 05:00, Azimuth: 60°, Elevation: -14° 06:19 09 12 15 18 19:49 Sun path, September Time: 06:00, Azimuth: 81°, Elevation: -10° Time: 06:49, Azimuth: 89°, Elevation: 0° Time: 07:00, Azimuth: 90°, Elevation: 1° Time: 08:00, Azimuth: 100°, Elevation: 12° Time: 09:00, Azimuth: 111°, Elevation: 23° Time: 10:00, Azimuth: 124°, Elevation: 33° Time: 11:00, Azimuth: 139°, Elevation: 42° Time: 12:00, Azimuth: 159°, Elevation: 48° Time: 13:00, Azimuth: 182°, Elevation: 50° Time: 14:00, Azimuth: 204°, Elevation: 47° Time: 15:00, Azimuth: 223°, Elevation: 40° Time: 16:00, Azimuth: 238°, Elevation: 31° Time: 17:00, Azimuth: 250°, Elevation: 21° Time: 18:00, Azimuth: 261°, Elevation: 10° Time: 18:58, Azimuth: 270°, Elevation: 0° Time: 19:00, Azimuth: 271°, Elevation: 0° Time: 20:00, Azimuth: 280°, Elevation: -12° 06:49 09 12 15 18 18:58 Sun path, October Time: 07:00, Azimuth: 100°, Elevation: -4° Time: 07:18, Azimuth: 103°, Elevation: 0° Time: 08:00, Azimuth: 110°, Elevation: 6° Time: 09:00, Azimuth: 121°, Elevation: 17° Time: 10:00, Azimuth: 133°, Elevation: 26° Time: 11:00, Azimuth: 148°, Elevation: 33° Time: 12:00, Azimuth: 165°, Elevation: 38° Time: 13:00, Azimuth: 184°, Elevation: 38° Time: 14:00, Azimuth: 202°, Elevation: 36° Time: 15:00, Azimuth: 218°, Elevation: 30° Time: 16:00, Azimuth: 232°, Elevation: 22° Time: 17:00, Azimuth: 244°, Elevation: 12° Time: 18:00, Azimuth: 254°, Elevation: 1° Time: 18:13, Azimuth: 256°, Elevation: 0° Time: 19:00, Azimuth: 263°, Elevation: -9° Time: 06:00, Azimuth: 91°, Elevation: -15° 07:18 09 12 15 18 18:13 Sun path, November Time: 06:00, Azimuth: 107°, Elevation: -10° Time: 06:53, Azimuth: 115°, Elevation: 0° Time: 07:00, Azimuth: 116°, Elevation: 0° Time: 08:00, Azimuth: 127°, Elevation: 10° Time: 09:00, Azimuth: 138°, Elevation: 18° Time: 10:00, Azimuth: 152°, Elevation: 25° Time: 11:00, Azimuth: 167°, Elevation: 28° Time: 12:00, Azimuth: 183°, Elevation: 29° Time: 13:00, Azimuth: 199°, Elevation: 27° Time: 14:00, Azimuth: 213°, Elevation: 22° Time: 15:00, Azimuth: 226°, Elevation: 15° Time: 16:00, Azimuth: 237°, Elevation: 6° Time: 16:40, Azimuth: 244°, Elevation: 0° Time: 17:00, Azimuth: 247°, Elevation: -4° Time: 18:00, Azimuth: 256°, Elevation: -15° 06:53 09 12 15 16:40 Sun path, today Time: 07:00, Azimuth: 100°, Elevation: -3° Time: 07:17, Azimuth: 102°, Elevation: 0° Time: 08:00, Azimuth: 110°, Elevation: 7° Time: 09:00, Azimuth: 120°, Elevation: 17° Time: 10:00, Azimuth: 133°, Elevation: 26° Time: 11:00, Azimuth: 148°, Elevation: 33° Time: 12:00, Azimuth: 165°, Elevation: 38° Time: 13:00, Azimuth: 184°, Elevation: 39° Time: 14:00, Azimuth: 202°, Elevation: 36° Time: 15:00, Azimuth: 219°, Elevation: 30° Time: 16:00, Azimuth: 232°, Elevation: 22° Time: 17:00, Azimuth: 244°, Elevation: 12° Time: 18:00, Azimuth: 254°, Elevation: 2° Time: 18:14, Azimuth: 256°, Elevation: 0° Time: 19:00, Azimuth: 264°, Elevation: -9° Time: 06:00, Azimuth: 91°, Elevation: -15° 07:17 09 12 15 18 18:14 Real-time Sun 216.73.217.172, 2026-10-20T08:08 © Gaisma.com

Sun path

 
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December solstice
 
Annual variation
 
Equinox (March and September)

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Solar ultraviolet (UV) radiation [?]

Rough clear sky estimates. Wavelengths: UVA λ=360 nm, UVB λ=300 nm. Source: CICARMA, Emanuela, et al. Sun and sun beds: inducers of vitamin D and skin cancer. Anticancer research, 2009, 29.9: 3495-3500.

  • Both UVA and UVB cause skin damage (sunburn, premature aging, skin cancer).
  • UVB is responsible for delayed tanning and burning.
  • UVA is responsible for the immediate tanning effect.
  • Exposure to UVB radiation helps the skin produce vitamin D (D3).
[?]
CICARMA, Emanuela, et al. Sun and sun beds: inducers of vitamin D and skin cancer. Anticancer research, 2009, 29.9: 3495-3500.
[?]
CICARMA, Emanuela, et al. Sun and sun beds: inducers of vitamin D and skin cancer. Anticancer research, 2009, 29.9: 3495-3500.
[?]
CICARMA, Emanuela, et al. Sun and sun beds: inducers of vitamin D and skin cancer. Anticancer research, 2009, 29.9: 3495-3500.
[?]
CICARMA, Emanuela, et al. Sun and sun beds: inducers of vitamin D and skin cancer. Anticancer research, 2009, 29.9: 3495-3500.
[?]
TSIARAS, William G.; WEINSTOCK, Martin A. Factors influencing vitamin D status. Acta dermato-venereologica, 2011, 91.2: 115-124.
Normalized dose rate
0 1.6
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Boulder, Colorado, United States - Seasons graph and Earth's orbit

Seasons graph Seasons graph requires SVG, so it cannot work on your current browser with its current settings. Sorry. © Gaisma.com 216.73.217.172, 2026-10-20T08:08 Winter - 2025-12-21 08:03 .. 2026-03-20 08:45 (88d 23h 42min) Spring - 2026-03-20 08:45 .. 2026-06-21 02:24 (92d 17h 39min) Summer - 2026-06-21 02:24 .. 2026-09-22 18:05 (93d 15h 41min) Fall - 2026-09-22 18:05 .. 2026-12-21 13:50 (89d 20h 45min) Today March equinox June solstice September equinox December solstice Aphelion Perihelion January February March April May June July August September October November December I II III IV V VI VII VIII IX X XI XII 0.98 AU = 146,605,913.286 km 1 AU = 149,597,870.7 km 1.02 AU = 152,589,828.114 km  0.98 AU  1 AU  1.02 AU Sun Variation of Earth's orbit, years 1600–2600 Earth's orbit (Min, years 1600–2600) Earth's orbit (Max, years 1600–2600) Earth's orbit (This year) Earth - Earth-Sun distance = 0.9958 AU ≈ 148,973,205 km

Events

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Today
▲
December solstice
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March equinox
▲
June solstice
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September equinox
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Perihelion [?]
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Aphelion [?]

Earth's orbit

 
This year
 
Min, years 1600–2600 [?]
 
Max, years 1600–2600 [?]
 
Variation, years 1600–2600

Seasons

 
Winter
 
Spring
 
Summer
 
Fall
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Event Date Time to
December solstice 2026-12-21 13:50 62d 12h 41min
March equinox 2027-03-20 14:24 151d 12h 15min
June solstice 2027-06-21 08:10 244d 6h 1min
September equinox 2027-09-23 00:01 337d 21h 52min

Boulder, Colorado, United States - Solar energy and surface meteorology

VariableIIIIIIIVVVIVIIVIIIIXXXIXII
Insolation, kWh/m²/day2.032.874.065.095.876.346.285.504.563.432.371.88
Clearness, 0 - 10.490.510.530.530.540.550.560.550.550.540.520.50
Temperature, °C-3.00-1.252.807.2713.0017.5520.7219.2914.958.400.90-3.31
Wind speed, m/s8.017.577.547.456.646.015.485.515.976.467.007.61
Precipitation, mm161940557851473640303019
Wet days, d5.55.98.88.310.48.79.49.26.95.25.66.1
These data were obtained from the NASA Langley Research Center Atmospheric Science Data Center; New et al. 2002
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Boulder, Colorado, United States - Basic information

Latitude: +40.015 (40°00'54"N)
Longitude: -105.27 (105°16'12"W)
Base time zone: UTC-7 hours [?]
Local time: 02:08
Continent: Americas
Sub-region: Northern America
Distance: ~1300 km (from your IP)
Altitude: ~1700 m
Boulder, nearby locations
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Solar terminator Boulder on world map. Features current solar terminator dividing day and dark sides of earth. Equator Prime Meridian Tropic of Cancer Tropic of Capricorn Arctic Circle Antarctic Circle © Gaisma.com 216.73.217.172, 2026-10-20T08:08 Antarctica Americas Africa Oceania a Oceania Europe Asia Sun Sun Sun Boulder

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