Duration of Daylight/Darkness Table for One Year

Important! Please read the Notes section.

This page provides a way for you to obtain a table of the duration of daylight or darkness for one year.

You can obtain a table for any location worldwide by following these simple steps:

Decide on which form to use. If you want a table for cities or towns in the U.S. or its territories, use Form A below. For other locations, use Form B below.
Enter the year (1700 - 2100) for which the table is desired.
Select the table type (daylight or darkness) from the pop-up list in the form that you are using.
Specify the location of interest using the fields provided on the form.
Click the "Compute Table" button at the end of the form to compute the table. The table will provide the data requested in hours:minutes format.
Be sure to read Notes section (on this page beyond the two forms) for an explanation of the items in the table.

Form A - U.S. Cities or Towns

Specify year, type of table, and place:

Year: Type of table:

State or Territory:

City or Town Name:

The place name you enter above must be a city or town in the U.S. The place's location will be retrieved from a file with over 22,000 places listed. Either upper- or lower-case letters or a combination can be used. Spell out place name prefixes, as in "East Orange", "Fort Lauderdale", "Mount Vernon", etc. The only exception is "St.", which is entered as an abbreviation with a period, as in "St. Louis". You need only enter as many characters as will unambiguously identify the place.

Form B - Locations Worldwide

Specify year, type of table, and place:

Year: Type of table:

Place Name Label:

The place name you enter above is merely a label for the table header; you can enter any identifier, or none (avoid using punctuation characters). The data will be calculated for the longitude and latitude you enter below.

Longitude: east west degrees minutes

Latitude: north south degrees minutes

Time Zone: hours east of Greenwich west of Greenwich

The Time Zone required is the standard time zone of the location (i.e. not the zone corresponding to Daylight Saving Time or Summer Time). For locations that require it, the time zone can be entered in hours and a fraction. For example, for locations in India, the time zone may be entered as 5.5 hours east of Greenwich. The time zone field can accommodate up to five characters.

Need coordinates? Try NGA's GEOnet Names Server (GNS). (Click on the "GNS Search" link at the top of the left frame.)
Need U.S. coordinates? Try the USGS Geographic Names Information System (GNIS).
Need a time zone? Try the time zone map.

Notes

Explanation

The Duration of Daylight table provides, for each calendar date, the total time that any portion of the Sun is above the horizon. Typically (for low and mid-latitude locations), this will be the elapsed time beginning at sunrise and ending at sunset.

The Duration of Darkness table provides, for each calendar date, the total time that the entire Sun is below the horizon. Typically (for low and mid-latitude locations), this will be the sum of two elapsed times: the time beginning at local midnight and ending at sunrise, and the time beginning at sunset and ending at local midnight.

The local times used in these calculations are based on the standard time zone of the location for places in the U.S. (Form A), or the input time zone (Form B).

For definitions of sunrise and sunset, see Rise, Set, and Twilight Definitions in our FAQ area.

For an explanation of why there is generally more daylight than darkness during the equinoxes (and all year at the equator), see Length of Day and Night at the Equinoxes and Comparative Lengths of Days and Nights.

How to Print the Table

The table is 112 characters wide, so to print it you must use landscape orientation and 8-point (smallest) type. Consult your browser's documentation for details on how to change the font/text size. An alternative scheme is to save the table to a file on your computer (for example, in Internet Explorer, click on File then Save As...), then use your favorite word processor or text editor to print it.

Need other kinds of astronomical information? Start at our home page.

Nov	DEC	Jan
	23
2006	2007	2008

home	site map	help	last modified: 12 September 2007 14:49