Chapchai, who had to return in the morning to complete his opening round, grabbed the outright lead with his flawless six-under-par 65.
The Thai then headed out to the Sentosa Golf Club soon after for his second round where he mixed two birdies against two bogeys in his back-nine before play was suspended again.
Tournament officials from the Asian Tour and European Tour are bracing themselves for a long weekend ahead and are not ruling out a Monday finish for the Barclays Singapore Open.
"At present, our aim is still to complete 72 holes, weather permitting. We hope to finish the second round at approximately 3.15pm tomorrow, at which time there will be a re-draw for round three, which will not start before 4pm.
The third and fourth rounds would then be played with the same draw, which would allow us to finish at approximately 5.15pm on Sunday, provided there are no further delays.
However, if we do suffer more delays we would then decide, in consultation with the sponsor and promoter, whether to reduce the tournament to 54 holes or complete the fourth round on Monday," said Jittisak Tamprasert and Jose Maria Zamora, tournament directors of the Barclays Singapore Open.
Dyson who was two shots back of Chapchai at the start of the second round, made up ground quickly with three birdies in his opening back-nine. He birdied the par-four first after making the turn and parred his next three holes before thunderstorms brought his charge to a halt.
With only one top-10 finish at the Asian Tour season-opening event in Myanmar to show for this season, Chapchai credited his return to the monastery for playing a huge role in shaping his mental ability.
"I've been going to the monastery a lot to calm myself. I used to be very hot-tempered and I get frustrated easily especially at such a young age. My temper is better now but I still try to go back to the monastery once in a while," said Chapchai.
The three-time Asian Tour winner also believed the time spent in ironing out his putting woes is slowly paying off.
"I've been having problems with my putting for the whole of this year. I try to make sure that I've got enough practice before coming to play here. It seems to be working out today," said Chapchai.
Meanwhile world number one Rory McIlroy of Northern Ireland will have to shrug off the effects of a cold if he wants to stay on course of winning the Barclays Singapore Open.
The tournament's marquee name signed for an opening 70 and ended his day at one-under-par through 12 holes.
"I'm struggling a bit with a cold or a sinus infection at the moment, so I'm not feeling 100 percent," said McIlroy, who is accompanied by tennis star and girlfriend Caroline Wozniacki in Singapore this week.
"The energy levels are fine, and maybe it's a good thing that the temperature and humidity is so high, because I might be able to sweat it out," added the world number one.
Richard Green leads the Australasians after his opening round of 69 but has not even started his second round, Marcus Fraser, Andrew Dodt and Michael Campbell are at 1 under and three time champion Adam Scott is at even par although he too is yet to get his second round underway.