Climate dictates what type of characteristics the fruit will bear hence the wines personality as well. Ridge Vineyards in Cupertino, California produced some fantastic Zinfandels which are made from fruit, i.e.. (grapes) that are grown in different regions in the area. Each growing climates lends a hand in the subtle nuances for each Zinfandel they produce. http://www.ridgewine.com

Generally, climates with relatively low rainfall are better (since moisture in the ground or on vines and grapes can cause mold or rot in canopy, fruit and root. Depending on the size of the drops rain can literally beat up blossoms causing "shatter" or uneven fruiting). Many of the "best" regions for wine are near bodies of water since oceans, rivers, lakes, etc can help to mitigate heat and are often planted for early sun (so the vines are not overstressed during the heat of the day). The preferred soil is often rocky, sandy or dominated by chalk (all of which make other agricultural endeavors difficult). Traditionally it is thought that struggling or stressed vines produce fruit with more distinct taste characteristics ("to make good wine, a vine must struggle"). If you look around the world at the variety of wine regions now available, you will realize that these are not hard and fast rules; merely the traditional Western European approach. Personally I believe that it does make better wine, but there is such a variety of wine in the world now that it is a shame to limit yourself to any particular region or style. Cheers!