Rainfall also decreases dramatically from east to west. Rainfall is generally highest in the months of May and September, but it is not at all uncommon for periods of 60 to 90 days to pass without significant rain. When it does rain, the Edwards Plateau can experience some of the highest rainfall intensities in the world. In 1935, D'Hanis received 22 inches of rain in less than three hours. In 1972, New Braunfels recorded almost 14 inches of rain in less than four hours.
Droughts can be just as severe as rainfall intensities.
The drought of '96 is regarded as being more severe than the drought of record in the 1950's, although it's duration was shorter. The variable nature of rainfall here and the geology of the Aquifer combine to have huge impacts on water availability for the region. To understand this, compare the Edwards limestone aquifer to a sand aquifer. One can recharge a sand aquifer by injecting water, and the water forms a stationary dome that remains in place. The water will still be there years later when you need to pump it out.