CEDAR RAPIDS, Iowa (KCRG-TV9) -- Monday is the first day of spring! While we’ve begun a new season, the vernal equinox lasts just a moment in time. That moment is when the Sun’s direct rays directly hit the Earth’s equator. That happened at 5:29 Central Daylight Time Monday morning. Because of the Earth’s tilt, the Sun’s direct rays will continue moving north until they reach the Tropic of Cancer on the first day of summer on June 20. Until then, the amount of daylight we have will keep getting longer.
Even though equinox means “equal night,” we do not, in fact, have 12 hours of daylight and 12 hours of darkness today. The length of day in Cedar Rapids is actually 12 hours, nine minutes, and 43 seconds. It’s longer than 12 hours for two reasons. First, sunrise is defined as when the top-most edge of the Sun’s disk crosses above the horizon, and sunset is when the top-most edge crosses below the horizon. Secondly, the Earth’s atmosphere bends light as it passes through, which means we see the Sun above the horizon longer than it actually is.