The chances are almost certain that residents waking up in the Tucson and Yuma, Arizona, areas in the American southwest desert, upon turning on their television or radio for a weather report, will hear the forecaster declare that "today will be another sunny day." This area receives sunshine on average 94 percent of the possible days during the year. Nearby Phoenix has an annual 85 percent sunshine possibility. But for those living in Vancouver, Canada, or Edinburgh, United Kingdom, the percentage of possible sunny days is only 31 and 33 respectively on a yearly average. For people who choose to live in a place where there is a moderate amount of daily sunshine, cities like St. Louis, Missouri, or Little Rock, Arkansas, may be more to their liking. There the sun tends to shine about two-thirds of the time.
The sun's rays are directly over some point on the earth between the Tropic of Cancer at 23.5 degrees north latitude on or about June 21 and the Tropic of Capricorn at 23.5 degrees south latitude on or about December 21. The sun is always directly over the Equator twice each year, once on or about March 21 and once on or about September 21. These changes of the position of the earth in relationship to the sun cause the seasons. The seasons, accordingly, are most instrumental in determining overall temperatures and thus a major factor contributing to man's activities and the ways he lives in both the Northern and Southern Hemispheres.
Many people seem to crave a "place in the sun." The old adage that there is "nothing new under the sun" is now being proven to be wrong in one respect. Medical research experts have found that there is a serious risk for prolonged exposure to the sun, including an increased incidence of skin cancer and cataracts, an eye disease. For this reason it is