The siren sounded after just under two hours of play had been possible at rain-softened Merion Golf Club where severe thunderstorms and high winds have been forecast for later in the day.
Luke Donald birdied three holes in a row from the 11th to move to the top of the leaderboard late in Thursday's weather-interrupted first round of the U.S. Open in his quest for a first major title.
Phil Mickelson rolled in an 18-foot birdie putt in fading light at the 18th hole to grab a share of the lead in Friday's second round of the U.S. Open when play was suspended due to approaching darkness.
Justin Rose produced remarkable poise and a Ben Hogan-like finish to win his first major title by two shots at the U.S. Open on Sunday after overhauling 54-hole leader Phil Mickelson in the final round.