The 22-year-old double major winner was one of 78 players who returned to the Sentosa Golf Club to finish their second rounds on Saturday but putter issues meant he could only sign for a one-under-par 70 and a share of seventh at five-under.
A frustrating round was compounded by an ugly six on the par-five 18th after he lipped out from five feet despite finding the centre of the fairway off the tee.
“The bogey did hurt on the last,” the American told reporters after he was forced to chip away from the hole when blocked by a greenside bunker.
“I made all my putts inside six feet yesterday but missed five or six today. I've just got to get comfortable on the shorter length putts.”
South Korean Song Young-han, one of the fortunate few to complete their second rounds on Friday, was the halfway leader after shooting an impressive eight-under 63 for a nine-under 36 hole total of 133.
First round leader Keith Horne of South Africa, one of the last to finish their second rounds on Saturday, was a shot back in second after signing for a 68.
World number 26 An Byeong-hun also completed his second round on Saturday, firing a two-under 69 to sit on seven-under alongside Japanese duo Shintaro Kobayashi (69) and Hideto Tanihara (67).
Spieth had managed to finish six holes of his second round on Friday before heavy rain and then lightning threats ended play early at the Asian Tour and Japan Golf Tour season opening event.
Back-to-back birdie threes from the 10th brightened his scorecard and he notched a two at the 17th but a poor bunker shot led to a bogey-five at the 13th and the frustrating finish stalled his progress.
Spieth was scheduled to have a two-hour break before starting his third round after 1 pm (0500 GMT) with more storms expected later in the day at an event employing preferred lies.
The Singapore Open, back after a three-year absence, has frequently been shortened to three rounds or extended to Monday because of stormy weather in the hot and humid Southeast Asian city-state.
“These kind of delays have happened before, in professional and college golf, you have to get used to it,” Spieth said.
“Got to be prepared to play a lot of golf.
“Need to post a good one this afternoon. The course is gettable.” – Reuters
Original source: Spieth left frustrated in Singapore