Sommers-Bausch Observatory - University of Colorado



Sunrises and Sunsets at Boulder, 2015


Data courtesy the

US Naval Observatory Astronomical Applications



Sunrise and sunset conventionally refer to the times when the upper edge of the disk of the Sun is on the horizon. Atmospheric conditions are assumed to be average, and the location is in a level region on the Earth's surface.

Horizon: Wherever one is located on or near the Earth's surface, the Earth is perceived as essentially flat and, therefore, as a plane. The sky resembles one-half of a sphere or dome centered at the observer. If there are no visual obstructions, the apparent intersection of the sky with the Earth's (plane) surface is the horizon, which appears as a circle centered at the observer. For rise/set computations, the observer's eye is considered to be on the surface of the Earth, so that the horizon is geometrically exactly 90 degrees from the observer's zenith.

             o  ,    o  ,                                  BOULDER, COLORADO                           Astronomical Applications Dept.
Location: W105 16, N40 01                          Rise and Set for the Sun for 2015                   U. S. Naval Observatory        
                                                                                                       Washington, DC  20392-5420     
                                                        Mountain Standard Time                                                        
                                                                                                                                      
                                                                                                                                      
       Jan.       Feb.       Mar.       Apr.       May        June       July       Aug.       Sept.      Oct.       Nov.       Dec.  
Day Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set  Rise  Set
     h m  h m   h m  h m   h m  h m   h m  h m   h m  h m   h m  h m   h m  h m   h m  h m   h m  h m   h m  h m   h m  h m   h m  h m
01  0723 1646  0710 1720  0635 1753  0545 1825  0501 1856  0434 1924  0436 1934  0459 1915  0529 1833  0557 1744  0630 1659  0703 1636
02  0723 1647  0709 1721  0633 1754  0544 1826  0500 1857  0434 1924  0436 1934  0500 1914  0530 1831  0558 1742  0631 1658  0704 1636
03  0723 1648  0708 1722  0632 1755  0542 1827  0459 1858  0434 1925  0437 1933  0501 1913  0531 1830  0559 1740  0632 1657  0705 1636
04  0723 1649  0707 1724  0630 1756  0541 1828  0458 1859  0433 1926  0437 1933  0502 1912  0531 1828  0600 1739  0633 1655  0706 1636
05  0723 1650  0706 1725  0629 1757  0539 1829  0457 1900  0433 1926  0438 1933  0503 1910  0532 1826  0601 1737  0635 1654  0707 1636
06  0723 1651  0705 1726  0627 1758  0537 1830  0455 1901  0433 1927  0439 1933  0504 1909  0533 1825  0602 1736  0636 1653  0708 1636
07  0723 1652  0704 1727  0625 1759  0536 1831  0454 1902  0432 1928  0439 1932  0505 1908  0534 1823  0603 1734  0637 1652  0709 1636
08  0723 1653  0702 1728  0624 1800  0534 1832  0453 1903  0432 1928  0440 1932  0506 1907  0535 1822  0604 1732  0638 1651  0710 1636
09  0723 1654  0701 1730  0622 1801  0533 1833  0452 1904  0432 1929  0440 1932  0507 1906  0536 1820  0605 1731  0639 1650  0711 1636
10  0723 1655  0700 1731  0621 1802  0531 1834  0451 1905  0432 1929  0441 1931  0508 1904  0537 1818  0606 1729  0640 1649  0712 1636
11  0722 1656  0659 1732  0619 1804  0530 1835  0450 1906  0432 1930  0442 1931  0509 1903  0538 1817  0607 1728  0641 1648  0713 1636
12  0722 1657  0658 1733  0618 1805  0528 1836  0449 1906  0432 1930  0443 1930  0510 1902  0539 1815  0608 1726  0643 1647  0713 1636
13  0722 1658  0657 1734  0616 1806  0527 1837  0448 1907  0432 1931  0443 1930  0511 1901  0540 1813  0609 1725  0644 1647  0714 1636
14  0721 1659  0655 1736  0614 1807  0525 1838  0447 1908  0432 1931  0444 1929  0512 1859  0541 1812  0610 1723  0645 1646  0715 1636
15  0721 1700  0654 1737  0613 1808  0523 1839  0446 1909  0432 1932  0445 1929  0512 1858  0542 1810  0611 1722  0646 1645  0716 1637
16  0721 1701  0653 1738  0611 1809  0522 1840  0445 1910  0432 1932  0446 1928  0513 1857  0543 1808  0612 1720  0647 1644  0716 1637
17  0720 1702  0652 1739  0610 1810  0521 1841  0444 1911  0432 1932  0446 1928  0514 1855  0544 1807  0613 1719  0648 1643  0717 1637
18  0720 1703  0650 1740  0608 1811  0519 1842  0443 1912  0432 1933  0447 1927  0515 1854  0545 1805  0615 1717  0649 1643  0718 1638
19  0719 1705  0649 1741  0606 1812  0518 1843  0443 1913  0432 1933  0448 1926  0516 1852  0546 1803  0616 1716  0651 1642  0718 1638
20  0719 1706  0648 1743  0605 1813  0516 1844  0442 1914  0432 1933  0449 1926  0517 1851  0547 1802  0617 1714  0652 1641  0719 1638
21  0718 1707  0646 1744  0603 1814  0515 1845  0441 1915  0432 1933  0450 1925  0518 1849  0548 1800  0618 1713  0653 1641  0719 1639
22  0718 1708  0645 1745  0602 1815  0513 1846  0440 1916  0433 1934  0450 1924  0519 1848  0548 1758  0619 1712  0654 1640  0720 1639
23  0717 1709  0643 1746  0600 1816  0512 1848  0439 1917  0433 1934  0451 1923  0520 1847  0549 1757  0620 1710  0655 1640  0720 1640
24  0716 1710  0642 1747  0558 1817  0511 1849  0439 1917  0433 1934  0452 1923  0521 1845  0550 1755  0621 1709  0656 1639  0721 1641
25  0715 1712  0641 1748  0557 1818  0509 1850  0438 1918  0433 1934  0453 1922  0522 1844  0551 1753  0622 1708  0657 1639  0721 1641
26  0715 1713  0639 1749  0555 1819  0508 1851  0438 1919  0434 1934  0454 1921  0523 1842  0552 1752  0623 1706  0658 1638  0721 1642
27  0714 1714  0638 1751  0553 1820  0506 1852  0437 1920  0434 1934  0455 1920  0524 1841  0553 1750  0624 1705  0659 1638  0722 1642
28  0713 1715  0636 1752  0552 1821  0505 1853  0436 1921  0435 1934  0456 1919  0525 1839  0554 1749  0625 1704  0700 1637  0722 1643
29  0712 1716             0550 1822  0504 1854  0436 1921  0435 1934  0457 1918  0526 1837  0555 1747  0627 1702  0701 1637  0722 1644
30  0711 1718             0549 1823  0503 1855  0435 1922  0435 1934  0457 1917  0527 1836  0556 1745  0628 1701  0702 1637  0723 1645
31  0711 1719             0547 1824             0435 1923             0458 1916  0528 1834             0629 1700             0723 1645

                                             Add one hour for daylight time, if and when in use.