Weaver was the runner-up in the 2012 U.S. Amateur at Cherry Hills (Colo.) Country Club, losing to Steven Fox in 37 holes. The finish earned him an exemption into the 2013 Masters, where he missed the cut, and the 2013 U.S. Open, where he finished 64th. He competed in the 2013 U.S. Amateur and advanced to the first round of match play, where he was defeated by Greg Eason, 21, of England, 3 and 2. Weaver was selected to compete in the 2013 Palmer Cup, where he recorded 1.5 points to contribute to Team USA’s victory. In 2013, the fifth- year senior at the University of California- Berkeley was named first-team All- American, All-West Region and All-Pac-12 selection. He recorded his first collegiate win at the 2013 NCAA Pullman Regional and placed runner-up at the Pac-12 Championship. He redshirted the 2011-12 season, and was the only amateur to qualify for the TPC Stonebrae Championship on the Web.com Tour, where he missed the cut. He recorded a victory at the Alameda Commuters and placed runner-up at the Fresno City Championship. In his sophomore season (2010-11), he finished T8th at the 2011 NCAA Championships and was an honorable mention to the Pac-10 All- Academic team.