Dave wrote: >The daylength at the equator *regardless* of your height (altitude) is precisely 12 hours every single day of the >year. Now this holds only directly on the equator. This is because the light always hits the earth exactly >perpindicularly (90 degrees) at the equator.
Actually, the sun is only directly over the equator (incident at 90 degrees) at the time of either equinox. When it is summer in the northern hemisphere, the sun is almost 90 degrees incident on the tropic of Cancer (23.5 degrees north latitude), and when it is winter up north the sun is almost directly over the tropic of Capricorn(23.5 degrees south latitude). This is because of the tilt of the Earth (about 23.45 degrees). So daylength does vary at the equator, being longest at the time of an equinox, and shortest at the time of a solstice. Helga Gray Wildcatt Database Co.
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