How Do You Measure A Sunny Day?

Tools

By By Steve Pool

SEATTLE - In Sept. 3's column, we talked about how Seattle is near the bottom in the U.S. with only an average of 58 sunny days a year. But it's not like a weather observer looks up at noon, sees the sun, and calls it a sunny day.

There are sensors that can actually measure when the sun is indeed shining on it. These sensors will track the number of seconds the sun was shining on it, and divide it by the number of seconds of daylight for that given day.

If the sun shone on the sensor for 70% or more of the day, it's considered a sunny day. If it was between 20-70% of the time, it was a partly cloudy day, and 20% or less, it's a cloudy day.

Your Photos

YouNews Weekend Planets and Moon(New) Weekend Planets and Moon
These images were all taken over the weekend of April 14 & 15. The images of Jupiter, Saturn and Mars are in the correct size ratio. The 2nd photo is a size comparison showing the correct size ratio with the moon.
YouNews Blood Moon from Puyallup Blood Moon from Puyallup
This is what two sisters get up to late at night, even when they are at opposite ends of the Pacific Coast.
YouNews Monday Full Moon Monday Full Moon
Took this image of the Full Moon Monday evening around 8:30pm. The skies toward the south east look pretty clear for the lunar eclipse but by 10pm it was pretty hopeless.
Taken with a 6 inch refractor and Nikon DSLR at 1/50 sec.
and ISO 100.