>>1528912>hailDepends on what size, but polycarbonate glazing will be the best bet.
>hurricaneYeah....well....that really depends on your luck doesn't it? Regardless, the best one will be polycarbonate glazing, masonry foundation, and metal framing. The framing will be very important. There are many cheap as dirt polycarbonate greenhouses with weak aluminum metal framing that are framed terribly. Thus, you'd need to get something with serious framing and sturdiness in mind. Depending on how large the greenhouse is, you may even consider affixing places on it to screw on plywood panels in the event of a hurricane coming. It'd add more structural support, protect from flying objects, and be easily removed/installed with a drill and screwdriver bit. You'd just need to find a place to store the plywood the rest of the year. You'd also need to disengage any automatic vent openers when everything is boarded up.
Also, the shape you make the greenhouse will play an important role in its stability for hurricane survival. You may want to use something like a geodesic dome greenhouse that uses steel construction and polycarbonate glazing. There are many companies that sell hurricane shelters that are geodesic domes since they are more wind resistant. Add earth embankments as structure (like in this image) with only the south side/sunny side of the window structure exposed to the sun. Couple all this with windbreaks, that do not obscure the sunlight, like low earthen embankments leading up to the greenhouse, and it will be the best possible greenhouse you could make that is hurricane proof
