What's more, the timing has changed too. In some parts of the United States, dry seasons are arriving earlier and wet seasons are starting later than they did 80 years ago. The time shift does not necessarily extend the length of dry or wet seasons, because most areas have transitional periods in between these precipitation extremes. In the Ohio River Valley, the fall dry season starts two to three weeks earlier today, the researchers report. In east New York, the wet season now kicks off on Jan. 8 instead of Feb. 1. And in the Southwest, the summer monsoon is starting later than it did during the middle of the 20th century. [In Images: Extreme Weather Around the World]
"The effects vary from region to region," said Indrani Pal, lead study author and a water resources engineer at the University of Colorado in Denver. "This study has a lot of implications from an ecology and water management perspective, and for extreme events like droughts and floods as well."



http://www.huffingtonpost.com/2013/07/26/weird-weather_n_3660229.html