Rate of Change in Daylight Hours

Although we can still expect a lot of winter weather ahead of us, the days are getting noticeably longer.  For example, Toronto will receive 54 more minutes of daylight per day at the end of January as compared to the beginning.  February will add another 1 hour 18 minutes per day.  A welcome change!!

Locations further south already enjoy more daylight than Toronto and their temperatures are warmer, however, they don't receive an increase in the hours of daylight to the extent that Toronto does.  For example, Miami will receive only 26 more minutes of daylight per day at the end of January as compared to the beginning, and February will bring only 38 minutes more.

Cheers, Ralph

Haiti - Daylight Availability

We have posted a free sunrise/sunset table for Port-au-Prince, Haiti, in support of those involved in rescue and relief work. The table provides rise and set times and the total number of hours of available sunlight for each day of the current month.

Definition of Sunrise/Sunset Times

The times of sunrise and sunset are by definition the times at which the upper edge of the sun appears on the horizon.  This assumes an observer on level ground with an unobstructed view to the horizon.  Official times take into account refraction (yes, light bends around the edge of the earth) under average atmospheric conditions.  When the top edge of the sun appears on the horizon, it is actually already about 34 minutes of arc below the horizon - that is, we can still see it, but it is actually below the horizon.

It is important to remember that rise/set times vary from place to place - they are very location-specific and it is not sufficient to look up the rise and set times for a place other than your own, and then to assume it applies for you.  If your location is not one of the samples posted on our web site, let us know and we will send you the rise/set times for the current month for your location for free. 

See http://www.sunposition.com/tables.html for details.

Cheers, Ralph

Vancouver 2010 Olympics Sun Tables

Free sunrise/sunset tables have been added for those of you visiting Vancouver or Whistler BC during the Olympics and Paralympics in February and March of this year.

February - Vancouver; Whistler

March - Vancouver; Whistler

These are technical, or official, times of rise and set based on an observer with an unobstructed view to a level horizon.  Local apparent times may vary - especially if the sun rises or sets behind mountains.

Cheers, Ralph