Online-Photoperiod Calculator

Author: J. Lammi  ( © 1996 - 2009) jjlammiyahoo.com

Computation of Daylengths, Sunrise/Sunset Times, Twilight and Local Noon

[Fail-safe mode] [Related stuff] [Send comments]

Select for dates Use the current date Input a date value	Select for locations Use menu of cities Input latitude	Daylight savings Set ON/OFF
Calculation Date Year	Month   January FebruaryMarch AprilMay JuneJuly AugustSeptember OctoberNovember December	Day 1 2345678 910111213141516 1718192021222324 25262728293031
Location	Utsjoki TornioOuluVaasaTampereTurku HelsinkiStockholmHamburgLondon BerlinParisViennaMunich Amarillo Tex. Anchorage Atlanta Baltimore ChicagoDallasDenverDetroit MIHonolulu HoustonLas VegasLos AngelesMiami MontrealNew YorkQuebecSan Francisco SeattleToronto Tokyo MelbourneSydneyBrisbaneAucklandCape Town Las PalmasHalifax Caninput
Latitude	° ´	N S   Find latitudes
Longitude	° ´	W E   Find longitudes
Local time	h min TZ	Timezones
Temperature	oC	Refraction

(C) 2009 J. Lammi (revised 25-Jun-03) Morning: - Begin of Nautical (= End of Astronomical) Twilight: Sun is 12 degrees below horizon - Begin of Civil (= End of Nautical) Twilight: Sun is 6 degrees below horizon - Sunrise: Sun is 0.83 degrees (= 50 arc-minutes) below horizon Noon: Sun is at meridian, max. altitude Evening: - Sunset: Sun is 0.83 degrees (= 50 arc-minutes) below horizon - End of Civil (= Begin of Nautical) Twilight: Sun is 6 degrees below horizon - End of Nautical (= Begin of Astronomical) Twilight: Sun is 12 degrees below horizon Solar radiation max power at noon, calculation for a constant extinction coefficient 0.9 assumed Solar azimuth: direction angle clockwise, north = zero, south = 180

Try to use the new fail-safe version if this version does not work properly for any reason.
The fail-safe version has no cookies to restore your location parameters.
New! See my Midnight Sun Pictures

Background photograph © J. Lammi 2009
Contacts: jjlammiyahoo.com

On Factors affecting Computation Accuracy

Browser requirement: Netscape Navigator 4.0 or MS Internet Explorer 4.0 at least
Last modified on 20. 09. 2009 23:39:42
Time now: 11. 03. 2010 03:49:39