Skiing the Cascade Volcanoes
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Table of Contents | Introduction | Ratings | WebCams | Bibliography | Highest Volcanoes | Snowfall & Snowdepth | Monthly Chart | Conifers | Compare | Distance | Sun Chart
Sunrise / Sunset Times for the Cascade Volcanoes       (page created February 2004, last updated May 2012)



During the spring and summer, the sun is the primary factor affecting the condition and quality of the snow surface. Maximum enjoyment (and often personal safety, too) depends on proper timing relative to sunhit on the slopes of interest for skiing and climbing. This page displays a table of the sunrise and sunset times throughout the year at several volcanoes spaced along the entire 750-mile (1200 km) length of the Cascade Range, along with a sun chart for each which shows the elevation and azimuth of the sun throughout the winter and spring. The equinoxes and solstices are highlighted in color in the table. The times for Civil Twilight (when the sun is less than 6° below the horizon) are also included, since during this period there is usually sufficient light for climbing or even skiing without artificial illumination. At these latitudes, twilight is longest at the summer solstice, shortest at the equinoxes (when the sun rises and sets at its steepest angle), and moderately long again near the winter solstice.
Note that on the sun chart, all times shown are in local standard time (not solar time) and unlike the table, the chart does not include Daylight Saving Time. The second half of the year is nearly symmetrical, so the sun chart's curve for May 21 also applies for July 21 (and Apr 20 for Aug 21, Mar 20 for Sep 22, etc.) with only a tiny shift of a few minutes in the local time.

Currently, values and charts have been calculated only for the 10 volcanoes listed in the menu, for the year 2004 (although DST is now calculated using the new law which went into effect in 2007). Solar times differ by only a few minutes for other years and at neighboring volcanoes, so this list should be sufficient for all practical purposes. Note that all calculations are made assuming a site at sea level at the given coordinates. At high elevations, the sun will rise several minutes earlier and set several minutes later. Varying atmospheric conditions which affect the amount of refraction of the sun's rays can also shift the rise and set times by several minutes. See the "Notes" at the bottom of the page for further info about these calculations.

Select a volcano from the menu at right to recalculate the first table and chart. The "Extended Version" has entries at roughly 10-day intervals, while the "Printable Format" produces a plain page without headers, footers, and text. The standard version in "Printable Format" will fit on a single printed page, but the "Extended Version" will not unless the font size is greatly reduced. Using "Landscape Format" will allow either version to fit on a single page printed in landscape orientation.

Select a date from the menu at right to change the date shown in the lower table, which compares the sunrise / sunset times on the summer and winter solstices and the selected day throughout the length of the Cascade Range.



Extended Version
Landscape Format
Printable Format
Show Lower Table in Printable Format

  Today
  Vernal Equinox   Autumnal Equinox


Crater Lake       Oregon       42.9° N, 122.1° W             Dates of Daylight Saving Time valid for 2014

    Date    .   Time  
Zone
  Twilight  
Begins
    Sunrise       Solar  
Noon
    Sunset       Twilight  
Ends
  Daylight  
Hours
 Twilight 
Hours
  Day +  
 Twilight 
 Maximum 
Solar Elev
 Sine (Max 
 Solar Elev) 
Jan 01   PST 7:07 AM 7:39 AM   12:11 PM   4:44 PM 5:17 PM 9:05 1:05 10:10 24.1° 0.408
Feb 01   PST 6:54 AM 7:24 AM   12:22 PM   5:21 PM 5:51 PM 9:57 1:00 10:57 29.6° 0.494
Mar 01   PST 6:15 AM 6:43 AM   12:20 PM   5:58 PM 6:27 PM 11:15 0:57 12:12 38.8° 0.626
Mar 20   PDT 6:43 AM 7:11 AM   1:16 PM   7:21 PM 7:50 PM 12:10 0:57 13:07 46.0° 0.720
Apr 01   PDT 6:21 AM 6:50 AM   1:12 PM   7:35 PM 8:04 PM 12:45 0:58 13:43 50.7° 0.774
May 01   PDT 5:31 AM 6:02 AM   1:06 PM   8:10 PM 8:41 PM 14:08 1:02 15:10 61.5° 0.879
Jun 01   PDT 4:58 AM 5:32 AM   1:06 PM   8:41 PM 9:15 PM 15:09 1:08 16:17 69.0° 0.933
Jun 21   PDT 4:54 AM 5:30 AM   1:10 PM   8:51 PM 9:26 PM 15:21 1:11 16:32 70.6° 0.943
Jul 01   PDT 4:59 AM 5:34 AM   1:12 PM   8:51 PM 9:26 PM 15:17 1:10 16:27 70.3° 0.941
Aug 01   PDT 5:28 AM 6:00 AM   1:14 PM   8:29 PM 9:01 PM 14:29 1:04 15:33 65.0° 0.906
Sep 01   PDT 6:04 AM 6:34 AM   1:08 PM   7:42 PM 8:11 PM 13:08 0:59 14:07 54.9° 0.818
Sep 22   PDT 6:28 AM 6:56 AM   1:00 PM   7:05 PM 7:33 PM 12:09 0:56 13:05 46.8° 0.729
Oct 01   PDT 6:38 AM 7:06 AM   12:57 PM   6:49 PM 7:17 PM 11:43 0:56 12:39 43.3° 0.686
Nov 01   PDT 7:14 AM 7:43 AM   12:51 PM   6:00 PM 6:29 PM 10:17 0:58 11:15 32.2° 0.534
Dec 01   PST 6:48 AM 7:20 AM   11:57 AM   4:35 PM 5:07 PM 9:15 1:04 10:19 25.2° 0.426
Dec 21   PST 7:04 AM 7:36 AM   12:06 PM   4:37 PM 5:10 PM 9:01 1:05 10:06 23.6° 0.400






Comparison of Longest and Shortest Days of Year with July 13



    Date    . Volcano     State /
  Province  
Location   Time  
Zone
  Twilight  
Begins
    Sunrise       Solar  
Noon
    Sunset       Twilight  
Ends
  Daylight  
Hours
  Twilight  
Hours
  Day +  
  Twilight  
  Maximum  
Solar Elev
 Sine (Max 
 Solar Elev) 
Jun 21     Mount Meager   BC   50.6° N, 123.6° W   PDT 4:16 AM 5:02 AM   1:16 PM   9:31 PM 10:16 PM 16:29 1:31 18:00 62.9° 0.890
Jun 21     Mount Garibaldi   BC   49.8° N, 123.0° W   PDT 4:19 AM 5:04 AM   1:14 PM   9:24 PM 10:08 PM 16:20 1:29 17:49 63.7° 0.896
Jun 21     Mount Baker   WA   48.8° N, 121.8° W   PDT 4:21 AM 5:04 AM   1:09 PM   9:14 PM 9:57 PM 16:10 1:26 17:36 64.7° 0.904
Jun 21     Mount Rainier   WA   46.9° N, 121.8° W   PDT 4:33 AM 5:13 AM   1:09 PM   9:06 PM 9:45 PM 15:53 1:19 17:12 66.6° 0.918
Jun 21     Mount Adams   WA   46.2° N, 121.5° W   PDT 4:36 AM 5:14 AM   1:07 PM   9:01 PM 9:40 PM 15:47 1:17 17:04 67.3° 0.923
Jun 21     Mount Hood   OR   45.4° N, 121.7° W   PDT 4:41 AM 5:19 AM   1:09 PM   8:59 PM 9:37 PM 15:40 1:16 16:56 68.1° 0.928
Jun 21     Three Sisters   OR   44.1° N, 121.8° W   PDT 4:48 AM 5:24 AM   1:09 PM   8:54 PM 9:31 PM 15:30 1:13 16:43 69.4° 0.936
Jun 21     Crater Lake   OR   42.9° N, 122.1° W   PDT 4:54 AM 5:30 AM   1:10 PM   8:51 PM 9:26 PM 15:21 1:11 16:32 70.6° 0.943
Jun 21     Mount Shasta   CA   41.4° N, 122.2° W   PDT 5:02 AM 5:36 AM   1:11 PM   8:46 PM 9:20 PM 15:10 1:08 16:18 72.1° 0.952
Jun 21     Lassen Peak   CA   40.5° N, 121.5° W   PDT 5:02 AM 5:36 AM   1:08 PM   8:40 PM 9:13 PM 15:04 1:07 16:11 73.0° 0.956
Jul 13     Mount Meager   BC   50.6° N, 123.6° W   PDT 4:34 AM 5:18 AM   1:20 PM   9:22 PM 10:05 PM 16:04 1:27 17:31 61.3° 0.877
Jul 13     Mount Garibaldi   BC   49.8° N, 123.0° W   PDT 4:37 AM 5:19 AM   1:17 PM   9:16 PM 9:58 PM 15:57 1:24 17:21 62.1° 0.883
Jul 13     Mount Baker   WA   48.8° N, 121.8° W   PDT 4:38 AM 5:18 AM   1:12 PM   9:07 PM 9:47 PM 15:49 1:20 17:09 63.1° 0.891
Jul 13     Mount Rainier   WA   46.9° N, 121.8° W   PDT 4:48 AM 5:26 AM   1:12 PM   8:59 PM 9:37 PM 15:33 1:16 16:49 65.0° 0.906
Jul 13     Mount Adams   WA   46.2° N, 121.5° W   PDT 4:50 AM 5:28 AM   1:11 PM   8:55 PM 9:33 PM 15:27 1:16 16:43 65.7° 0.911
Jul 13     Mount Hood   OR   45.4° N, 121.7° W   PDT 4:55 AM 5:32 AM   1:12 PM   8:53 PM 9:30 PM 15:21 1:14 16:35 66.5° 0.917
Jul 13     Three Sisters   OR   44.1° N, 121.8° W   PDT 5:01 AM 5:37 AM   1:13 PM   8:49 PM 9:24 PM 15:12 1:11 16:23 67.8° 0.926
Jul 13     Crater Lake   OR   42.9° N, 122.1° W   PDT 5:08 AM 5:42 AM   1:14 PM   8:46 PM 9:20 PM 15:04 1:08 16:12 69.0° 0.933
Jul 13     Mount Shasta   CA   41.4° N, 122.2° W   PDT 5:14 AM 5:47 AM   1:14 PM   8:42 PM 9:15 PM 14:55 1:06 16:01 70.5° 0.942
Jul 13     Lassen Peak   CA   40.5° N, 121.5° W   PDT 5:15 AM 5:47 AM   1:11 PM   8:36 PM 9:08 PM 14:49 1:04 15:53 71.4° 0.948
Dec 21     Mount Meager   BC   50.6° N, 123.6° W   PST 7:34 AM 8:14 AM   12:13 PM   4:12 PM 4:51 PM 7:58 1:19 9:17 15.9° 0.274
Dec 21     Mount Garibaldi   BC   49.8° N, 123.0° W   PST 7:29 AM 8:07 AM   12:10 PM   4:14 PM 4:52 PM 8:07 1:16 9:23 16.7° 0.287
Dec 21     Mount Baker   WA   48.8° N, 121.8° W   PST 7:21 AM 7:58 AM   12:05 PM   4:13 PM 4:51 PM 8:15 1:15 9:30 17.7° 0.304
Dec 21     Mount Rainier   WA   46.9° N, 121.8° W   PST 7:15 AM 7:50 AM   12:05 PM   4:21 PM 4:57 PM 8:31 1:11 9:42 19.6° 0.335
Dec 21     Mount Adams   WA   46.2° N, 121.5° W   PST 7:11 AM 7:46 AM   12:04 PM   4:23 PM 4:58 PM 8:37 1:10 9:47 20.3° 0.347
Dec 21     Mount Hood   OR   45.4° N, 121.7° W   PST 7:10 AM 7:44 AM   12:05 PM   4:27 PM 5:01 PM 8:43 1:08 9:51 21.1° 0.360
Dec 21     Three Sisters   OR   44.1° N, 121.8° W   PST 7:06 AM 7:39 AM   12:05 PM   4:32 PM 5:05 PM 8:53 1:06 9:59 22.4° 0.381
Dec 21     Crater Lake   OR   42.9° N, 122.1° W   PST 7:04 AM 7:36 AM   12:06 PM   4:37 PM 5:10 PM 9:01 1:05 10:06 23.6° 0.400
Dec 21     Mount Shasta   CA   41.4° N, 122.2° W   PST 7:00 AM 7:32 AM   12:07 PM   4:43 PM 5:14 PM 9:11 1:03 10:14 25.1° 0.424
Dec 21     Lassen Peak   CA   40.5° N, 121.5° W   PST 6:55 AM 7:26 AM   12:04 PM   4:43 PM 5:14 PM 9:17 1:02 10:19 26.0° 0.438



Notes:
The sunrise, sunset, and twilight values in the tables were calculated using online programs from the U.S. Naval Observatory, Astronomical Applications Department.
The sun charts were produced using an online program from the University of Oregon Solar Radiation Monitoring Laboratory.
An excellent source of information and formulas about solar angles and power is the online book Power From The Sun by William Stine and Michael Geyer.

The time of "Solar Noon" varies throughout the year by about 31 minutes, due to both the tilt of the Earth's axis and the elliptical form of the Earth's orbit around the Sun. This difference between mean solar time and true solar time on any day is given by the "equation of time" (see Power From The Sun, section 3.1 and Wikipedia: Equation of time). Disregarding the one-hour offset due to Daylight Saving Time, the earliest solar noon relative to Standard Time occurs around November 3, while the latest occurs around February 12.
The column "Maximum Solar Elev" lists the maximum elevation angle above the horizon reached by the sun (at the time listed for "Solar Noon"), which is given by:
        maximum solar elevation = 90° - abs( latitude - declination angle ). ..
This varies seasonally by 47° between the summer and winter solstices, equal to twice the 23.5° tilt of the Earth's axis.
The column "Sine (Max Solar Elev)" lists the sine of that angle, which is proportional to the maximum solar radiation received by a flat surface at solar noon on a clear day. The solar irradiance (power per unit area) incident on a flat surface at sea level at solar noon on a clear day (as would be measured by an optical pyranometer, see Power From The Sun, chapter 2) is approximately:
        maximum irradiance = 1000 * sin( maximum solar elevation ) W/m2. .
This varies seasonally between the summer and winter solstices by a factor of roughly 2.2 at 40° N latitude, increasing to a factor of 3.2 at 50° N. In the summer, the geographic variation in irradiance is small, with the southern end of the range at 40° N receiving only about 7% more on the summer solstice than the northern end at 50° N. The geographic variation is much larger in winter, with about 60% more irradiance on the winter solstice at 40° N than at 50° N.
The declination angle is the angle between the Earth's equatorial plane and a line connecting the centers of the Earth and Sun. For dates other than the solstices (when the declination angle is equal to the tilt of the Earth's axis, +/- 23.5°), this uses an approximate formula given in Power From The Sun, equation 3.7:
        declination angle = 180/π * asin( 0.39795 * cos( π/180 * 0.98563 * (day of year - 173) ) ). ..
This formula has a maximum error of about -1 degree for dates near the vernal equinox (March 20) due to the elliptical shape of Earth's orbit, and accuracy is much better during other seasons.


Version History

1.0
14 Feb 2004
First online release. Includes basic table (with sunrise/sunset and twilight times, along with calculations of daylight and day+twilight hours) and sun chart.
1.122 Feb 2004 Added "Extended Version" and "Printable Format" options.
1.1.124 Jan 2005Minor update to PHP/MySQL connection.
1.1.225 Apr 2005Minor update to PHP/MySQL connection.
1.202 Oct 2009 Fixed calculation of DST to reflect new 2007 DST rules. Added "Landscape Format" option. Added this Version History.
1.302 Oct 2009 Added second table for "Comparison of Longest and Shortest Days of Year", including maximum solar elevation.
1.404 Oct 2009 Expanded second table to include comparison with any selected day, which requires actually calculating the declination angle to get the maximum solar elevation.
1.4.105 Oct 2009 Added maximum solar elevation to first table. Minor graphical updates.
1.512 Oct 2009 Added calculations of solar noon and twilight hours to both tables.
1.5.114 Oct 2009 Added direct links for comparisons with equinoxes. Minor code tweaks.
1.623 Oct 2010 Added calculations of sine of maximum solar elevation to both tables. Expanded "Notes" above substantially.
1.6.114 May 2012 Remove deprecated parameter in mktime() function due to changes in PHP 5.3.0.

Table of Contents | Introduction | Ratings | WebCams | Bibliography | Highest Volcanoes | Snowfall & Snowdepth | Monthly Chart | Conifers | Compare | Distance | Sun Chart
Ski Mountaineering Photos & Trip Reports Equipment & Info Cascade Volcanoes Ring of Fire Site Map

Amar Andalkar   Seattle, WA, USA   <About the Author / Contact Me>
All material on this website is ©1997-2014 by Amar Andalkar unless otherwise noted.
Last modified Monday, May 14, 2012