Depends on what you mean by "this area". I was looking up average annual rainfall for Texas cities yesterday, to see if my new location is drier or wetter than my current one (somewhat wetter). Sherman gets just over 49 inches per year. The second or third year I lived there we had over 60 inches, which is rain forest level. Dallas is at about 36 inches per year, IIRC. San Antonio only about 22.
You're looking at averages; it's in real life, where you get years with plenty of rain throughout (like this year) and years where the ground is so dry that crevices open up down to the 'white rock'; it those latter years that 'kill trees' that I'm talking about.
There is also a N-S dividing line between Dallas and Ft Worth from which the 'average' rafinfall picks up dramamatically - this is owed to the 'path' Gulf moisture makes in it's trip northward ..