Timing of Precipitation

Distribution of precipitation during the year differs among regions within the Great Plains.

• Most of Texas and Oklahoma have pronounced bimodal regimes with peak levels of rainfall occurring both during May-June and September-October.

• In contrast, most of the rest of the Great Plains has a unimodal regime with peak precipitation occurring only during May or June.

• Regardless of the regime, 70 to 75% of the annual precipitation occurs during the growing season.