One of the rituals of my morning cup of coffee is checking where the rising sun casts its rays across the living room. At winter Solstice, the light shines in my eyes through the window in the southeast corner. Little by little, the sun rises farther north on the horizon. Each day, the sunbeams land more and more to my right. After a few weeks, the sun no longer shines in my eyes through that window. Not until the sun shines through the next window north am I blinded again. Our living room windows act as a kind of seasonal sundial.
By summer Solstice, the rising sun shines in my eyes through a north window. That is, if I get up early enough. Sunrise time shifts from 7:43 am at winter solstice to 5:30 in the morning at summer Solstice (it would be 4:30 am if we stuck to standard time). The daily change is gradual but the rate of change is not constant. Sunrise time changes rapidly during the period around each equinox but slows down around the solstices.
The daily change in sunrise approaching spring Equinox is something we feel in our bones. Nature feels it, too, as the romantic activities of breeding birds gets insistent. The quickening of perennial herbs begins in January, with expanding leaves practically jumping out of the ground. Buds are bursting on trees and shrubs while the number of wildflower blooming keeps increasing until the peak in April or May.
David Wagner is a botanist who has worked in Eugene for more than 40 years. He teaches moss classes, leads nature walks and publishes the Oregon Nature Calendar. For information about getting the 2021 Oregon Nature Calendar, contact him directly at firstname.lastname@example.org.