Very hot weather has come to Kern County and all of southern California. Santa Ana winds are the extremely hot and dry winds that affect this area beginning about this time of the year.

They are brought about by the first big cold pushes which move into the Great Plains. Snow and gusty north winds usually accompany these systems well to our east. But out here on the west side of the pattern those winds are easterly as they circulate clockwise around a large high pressure ridge. Downsloping from the desert, the winds are bone dry and quite hot. They promote extreme fire danger. Our current situation is expected to come to an end by the early part of next week as a trough comes to the west coast with welcomed cooling.

Even though the autumnal equinox occurred on Tuesday at 2:18 PM, it isn’t until this Saturday (the 26th) that we actually have 12 hours of both daylight and nighttime. Why the disparity? It has to do with the sun’s disk. Celestial computations are made based on the center of a planet or star. That means the center of the sun, as viewed from the earth, crossed into the southern hemisphere on Tuesday at the autumnal equinox. However, sunrise and sunset are based on when the edge of the sun either first appears at sunrise or is last seen at sunset. Half the sun’s disk, amounting to 16 arc seconds, takes an additional 3 to 4 days to cross the horizon. Thus, the 12-hour point is always a few days after the autumnal equinox and always a few days before the vernal (spring) equinox. For the record, we experience a total of 12 hours and 8 minutes on this, the supposed equinox. Equinox, by the way, means “equal night”.