Conditions took a turn at the start of the earlier Moto2 race, which was forced to be delayed as the field switched from slick tyres to wets.
Shortened from 24 laps to 16, the Moto2 race didn’t get to the 2/3 cut-off distance to declare a result when heavy rain lashed the circuit.
A five-lap sprint was due to finish the Moto2 contest, but had to be abandoned when the rain intensified on the sighting lap to the grid.
A result was declared and half points awarded, with Marc VDS rider Tony Arbolino securing a maiden win in the Moto2 class.
With a result declared around half an hour before the MotoGP race was due to start and no easing of the rain, a further delay has been called.
Pitlane will open at 3:35pm local time, with a scheduled race start of 3:55pm and will run over 25 laps instead of 26.
Pitlane will remain open for 10 minutes to allow riders to make multiple sighting laps to assess the conditions before lining up on the grid.
Despite the poor forecast all weekend, the race will be the first wet session for the MotoGP class.
The race was due to get underway at 3:55pm local time following a 55-minute delay.
Following a number of sighting laps when pitlane opened at 3:35pm, a number of riders were seen in deep discussions between each other and representatives from Dorna Sports about the conditions.
This is the second time in 2022 that a race start has been pushed back due to bad weather, with the Indonesian GP at Mandalika in March delayed for the same reason.
With charter flights booked for the paddock on Sunday night, it is unlikely the Thai GP could be rescheduled to Monday – as was the case back in 2009 when the Qatar GP couldn’t run on Sunday due to bad weather.
The Thailand race was due to get underway at 3pm local time, with sunset in the region at around 6pm, giving MotoGP a decent window to run the grand prix before light fades.
VR46 Ducati rider Marco Bezzecchi will start on pole for the first time, with factory Ducati rider Francesco Bagnaia the leading championship challenger in third.
Championship leader Fabio Quartararo will start in fourth on his Yamaha, while Aprilia’s Aleix Espargaro is down in 13th as he has struggled on the stiffer rear slick tyre carcass brought to Thailand by Michelin to cope with the extreme temperatures.
Bagnaia struggled massively in the wet qualifying session last time out at the Japanese GP, the Ducati rider over two seconds off the pace down in 12th.
In the wet Indonesian GP, Bagnaia was a distant 15th, while Quartararo guided his Yamaha to second having made a breakthrough on the M1 in rain conditions.
Aprilia’s Espargaro also had a similarly difficult time at the Indonesian GP as he took the chequered flag in ninth – though he was sixth in wet qualifying in Japan.
Coming into the Thailand race, 25 points covers Quartararo, Bagnaia and Espargaro – with Quartararo 18 clear of Bagnaia at the head of the championship.