just saw this thread in a random comment...
seasons are regulated by the earth's tilt. when your hemisphere (either north or south) is tilted toward the sun, you get summer, because the sun's rays are more direct. the equator has summer basically all year round, because the tilt of the earth isn't as severe to them, and they get fairly direct rays. Since the tilt of the earth is like 20 degrees, if you live directly on the equator you get hit by the sun by rays (throughout the year) that range in the 0-20 degree range. Assume you live halfway between the equator and north pole, say North Carolina, it'd be more like 25 (summer) - 65 (winter). These are all noon-time values, with the extremes being on the solstices.

If you're at the arctic circle, then your sunlight comes at a value between 50 and 90 deg (where at noon you get the slightest peek at the sun, right on the horizon) anything higher than that and you get no sun at all on the solstice, higher and you get more days with no sun in winter.

Interestingly, I think if you live directly on the equator, then spring(around May) and fall(around October) are you're hottest seasons, and summer(June) and winter(Feb) are you're coolest.