The Hall of Famer overcame the tough conditions at Stockton Seaview Hotel and Golf Club to match the low round of the day and finish at 4-under-par 209, notching her 39th LPGA title
It was Webb's first win since the 2011 RR Donnelley LPGA Founders Cup.
Shanshan Feng, who came into the third round with a three-stroke lead, tumbled to a 4-over 75 Sunday, ending alone in second place at 2-under.
Hee Young Park grabbed third at minus-1 after registering a final-round 71.
Ending in fourth at even-par 213 was Jenny Shin (70).