California is the top apricot-producing state in the US. Apricot production moved from the San Francisco Bay area to the San Joaquin Valley after WWII. Contra Costa, Merced, San Benito, and Stanislaus counties should also be mentioned.
Three-quarters of all US apricots are grown in California these days, primarily in the state's dry and arid valleys. That's because their desert climates have long, warm, sunny days followed by cool nights, which is ideal for apricot growth. It also gives them the wintry chills they need to bud, yet the desert is unlikely to provide a harmful spring frost. The state's hot and dry summers also reduce pest and disease-related risk factors.
Historically, US production of apricots wasn't successful until the fruit was brought to California from Virginia, per the University of California. Meanwhile, the cooler (temperature) state of Washington accounts for nearly 25% of US apricots, and a few other states -like Utah- contribute as well.
Apricot season in California runs from mid-May to July, Washington's season runs from late June to early August, and Utah's is from early June to mid-August. Whether they come from California, Washington, or Utah, apricots are refreshingly sweet but take a lot to grow.
Source: tastingtable.com