More daylight...

At 47 degrees North, daylight hours in Seattle vary between 8 in December to 16 hours in June. Combined with a seemingly perpetual overcast, the limited daylight makes for dark and dreary winters. By the time my birthday rolls around in early March, the days are getting longer by 3 minutes & 20+ seconds for the next 6 weeks. We get nearly 3 hours more daylight from March 1 to April 30.

I love it as the days get longer knowing that spring and summer will last until the Fall. Okay, that was stating the blindingly obvious, but I do relish in my numerology (my favorite word to misuse) of knowing it will be warmer and sunnier for the next six months.

One astronomical oddity is that on March 18th, we will have 12 hours 2 minutes of daylight and yet the Spring equinox is not until March 20th at 7:21 EDT. Seems like the equinox ought to be on the 18th. Further wiki research reveals the reason for that.

Equilux: 1. the Sun appears as a disk in the sky with a radius of around 16 arcminutes, and so the top of the Sun appears to rise while the centre of the disk is still below the horizon, and the instant of the equinox is measured with respect to the Sun’s centre, and; 2. the Sun’s light is bent, or refracted, in the Earth’s atmosphere, so that rays from the Sun can light you up even before the Sun rises, and keep you lit after it sets, with the degree of refaction being around 34 arcminutes. These two factors combine to mean that the Sun will appear to have “risen” when the centre of the disk is still 50 arcminutes (16 + 34) below the horizon, making the amount of daylight longer than the expected 12 hours. How much longer depends on where on Earth you are. For example, in the UK the length of the day is approx. 12 hours 10 minutes, rather than exactly 12 hours.

I am grateful for more daylight hours and warmer days!