3/06/2007

My daylight analysis

I'm impatient for long days.

Googling around, I found this new service from the US Naval Observatory web page that generates a customized duration of daylight/darkness table for one year for up to 22,000 U.S. locations. (Click on "Data Services".)

Yesterday, I learned that San Francisco got 11 hours and 31 minutes of daylight. Moreover, we'll get 30-minute increases of daylight every 12-14 days until May 27, by which point we'll have 14.5 hours of daylight every day.

After May 27, the rate of increase slows down until we reach our maximum on June 18: 14 hours and 47 minutes. We get that 14 hours and 47 minutes for seven days in a row! Then the daylight begins to decrease. But it's not until August 4 that it falls off at the rate of 30-minutes every 12-14 days.

December 18 through December 25 are our darkest days: only 9 hours and 33 minutes of daylight.

6 comments:

mmw said...

That's awesome. I've just noticed the rate of change really pick up in the last week or so.

chigiy Binell said...

I've heard that March 31 has an1 and1/2 hours more daylight than March 1, and that the biggest increase in daylight is in the month of March. Enjoy all that daylight.

chuck b. said...

Not in San Francisco. I'll get an hour and five minutes more at the end of March than I got at the beginning.

People north of here will get more.

lisa said...

And here I thought you got more light than us in the North, period. Who knew...

chuck b. said...

The closer you live to the equator the closer you are to having a 12 hour maximum. At the poles it can be sunlight for 24 hours. Because the earth is tilted on its axis...

lisa said...

Ah...I knew I should have paid more attention in Earth Sciences class! It's just that my teacher got this white spitball on his lip during lecture... :(