I've had excellent results in SW PA with Cover-It and Shelter Logic brands quonset style. The two I have now are 12x20 and I use them for storing lawn equipment, tractor, implements, snow plow and other stuff I want to keep out of the weather but not in the garage -- even kept a car in one for awhile. I made a mechanism for the door similar to roll-up blinds, which makes it much easier to get in and out of -- teksupply may sell this as a kit now. I recommend anchoring the thing solidly to the ground with screw-in anchors, as well as installing a vapor barrier on the ground and louvers on both ends for ventilation.
You really do get what you pay for with these things. The metal struts and heavy duty canvas versions hold up much better than the cheap ones available at Tractor Supply and Sams Club.
Ken