We live within northeast wyoming. Is Zoysia grass a well brought-up alternative for this nouns? We have almost 13 inches of rain per year. The ground...

We have almost 13 inches of rain per year. The ground is terrifically rocky. We need something tough and that will survive hot dry summers and cold winters.
Answers:    I'd suggest buffalo grass, Buchloe dactyloides -- it's aboriginal and very hardy, and can filch both your heat and cold, and like 10-25" of water a year. Grows to give or take a few 5" tall within summer, so rarely requests mowing. It's shade-intolerant... more than half a day's shade or sandy soil resources you probably ought to think almost blue grama, Bouteloua gracilis -- but I don't like it as capably as a lawn.

Zoysia is going to winterkill at something like -10oF -- I believe you're likely to experience -20 or lower contained by your area.

More on buffalograss as a sward grass:
http://www.highcountrygardens.com/catalo...
Blue grama:
http://www.colostate.edu/Depts/csuturf/p...
Yes.