Firefighters in the Phoenix suburb of Tempe say it happened Monday afternoon as the woman picked up her child from day care.
Assistant Chief Andrea Glass says the woman happened to be walking under the tree where the hive was when wind blew it off.
The National Weather Service says wind gusts around metro Phoenix reached 45 mph.
Glass says the woman was stung 20 to 30 times on and around her head.
She was evaluated and opted to have her husband drive her to a hospital.
Firefighters sprayed the hive with foam because of its proximity to the day care and a school.