The relative humidity varies considerably in Arizona, during the day. The state does get Ocean air currents coming off Baja California, and when it does rain, it often comes in gulley washers. Those changes can be very hard on any exposed metals. I grant that Arizona rarely sees the kind of cold and snow we get here in Illinois, and its annual rainfall is much less than here. I live in a band in the middle of Illinois, where the Great Lake Effect does not often get this far South, and where the Gulf Effect does not reach this far North. When we have had winter blizzards, they are just as likely to be the result of heavy winter storms in the Gulf as they are from an " Alberta Clipper". If you take a look at an Illinois map, Illinois Rte 17 meets Illinois Route 45 in Iroquois County near a small town called " Thawville". It got its name because it represents the dividing line between the Great Lakes effect, and the Gulf Effect. That is about 50 miles North of where I live. In the Blizzard of Jan. 1965, we drove OUT of the snow at Dwight, on Ill. Rte. 47, and Rt. 17. Literally, it was snowing on the South side of the Intersection and clear on the North side, as we crossed Rt. 17, heading home to the suburbs of Chicago.
This quirk in the weather, and our " Corn Belt" which is roughly 160 miles wide, running from Interstate 70 on the South, and Interstate 80 on the North are the reasons Illinois is such a successful producer of Corn and Soybeans.
Our heavy humidity comes usually in August, when you can watch late planted corn stalks actually grow before your eyes. Keeping rust off metal in August around here takes constant work, unless the metal is kept in an air conditioned environment. Some of us are old enough to remember surviving the summer heat by sitting in front of floor fans that blew air across a tray of water- sometimes with ice in it.
