Buriram - A seasonal downpour soaked the track at Thailand's MotoGP on Saturday, delaying qualifying day and creating challenging conditions for riders.
Workers in ponchos swept water off the circuit as a safety car did test laps.
The morning session was "delayed due to weather conditions", MotoGP said on its official Twitter account.
It briefly resumed as rains tapered off 80 minutes past start time but the track was still wet and premier class riders waited for conditions to improve.
The race is being hosted for the second year in a row in the small northeastern Thai town of Buriram, which has boomed on the back of multi-million-dollar investment in sports infrastructure.
Clear skies prevailed throughout the inaugural event last year on the $60 million, Hermann Tilke-designed Chang International Circuit, which is Formula 1 grade.
But it is scheduled towards the tail end of monsoon season, and rain and humidity are expected.
On a balmy Friday practice Spaniard Marc Marquez had what he called a "nightmare" crash but was back on form in the afternoon session.
Honda's Marquez has a comfortable lead and is looking to secure his sixth MotoGP title in Buriram with only five races including Thailand left in the season.
But it was Italian and Petronas Yamaha rider Fabio Quartararo who recorded the fastest lap in Friday's afternoon practice at 1:30.404.