Sorry about my tossing in a monkey wrench! Even here on my tiny island there seem to be different zones. 28 miles long, seven at the widest, dry and cactus on the windward east end, wet and jungly on the west..
I lived in an apartment way high, altitude about 900 feet above sea level, high for here anyway, and it was much much cooler than another place I lived that was inland and low. At the same lattitude, Puerto Rico has mountains taller than 3,000 feet that can get much cooler than here.
Another consideration for zones is day/night length. (O NO!! another monkey wrench!!) The days/nights are about 13/11 hours in the summer, and opposite that in the winter.
Tomatoes simply will not pollinate here in the summer. The days are 85-95, and nights are 80-82, and it's just too hot. Tomatoes are a winter crop, just beginning to appear now in December. Spinach sprouts and keels over in a few days.
I would like southern limits for plants, how far south can this or that peach or apple be grown? How about berries? I heard of a tropical blackberry, but couldn't find one for sale. Cold tolerance isn't an issue, hey?
Yes, the closer to the equator, the more equal the days. And the higher the elevation, the cooler.
I could go on, but this is enough for one post!! Before I am banned!
