There are only a few factors concerning climate that would discourage you from building in a location. One is precipitation. You should have at least five inches of total annual precipitation per year. If your area does not see that amount of precipitation then you should have a water table of less than sixty feet so you can pump with a solar well into your cisterns. You can pump from deeper but it gets expensive fast.
You should also look at available sunlight per year. If you have very little, you will need back up electricity of some kind, such as wind, hydro or conventional grid. The newer solar panels are starting to be close to 40% efficient on cloudy days, however, soon the technology will exist for power to be made just from the light through the clouds.
The beauty of the Earthship concept is that it makes all of its own utilities so you can find really cheap land where there is no hope for utilities. You can find hard to get to but extremely beautiful land that no one would ever think to build on and find it for a good price. The nature of an Earthship allows for building in remote locations and can thus save a lot of money in the purchase of your land.