Surfing's first Olympic finals are to brought forward 24 hours to Tuesday because of the tropical storm set to hit Tokyo.
The predicted high winds are expected to deliver better waves, persuading Games officials to adjust the surfing schedule.
But rain and wind delayed the start of the women's triathlon on Tuesday morning by 15 minutes.
That made for dangerous conditions on the bike leg, with Australians Ashleigh Gentle, Emma Jeffcoat and Jaz Hedgeland racing.
While the rain eased after the 1.5km swim, Russian Federation triathlete Anastasia Gorgunova and New Zealander Ainsley Thorpe crashed out early in the 40km cycle, with the 10km run to come.
Australian surfing stars Sally Fitzgibbons and Owen Wright revelled in the windier conditions to book quarter-final berths on Monday and might benefit from the tropical storm in their pursuit for gold.
"After a review of the surf conditions forecast for Tuesday and Wednesday, tournament officials have decided to move the women's and men's Olympic surfing finals from Wednesday to Tuesday," said a Games statement.
"The International Surfing Association technical director assessed the overall impact of the surf forecast on the final day of competition and adjusted the schedule."
The men's quarter-finals will now take place from 8am (all times AEST), followed by the women's quarter-finals from 10.24am.
The men's semi-finals have been scheduled to commence at 12.48pm with the women's semi-finals from 2pm.
Bronze medal heats will start at 3.16pm (men) and 4.01pm (women), with the men's gold medal to be decided from 4.46pm and the women's from 5.31pm.
Tokyo organisers had said earlier they were not planning to reschedule more events for the Games as tropical storm Nepartak churned toward Japan's main island.
Rowing and archery events have been moved due to the storm, which is expected to head over Japan's north-east coast on Tuesday and could bring heavy rain to the capital.
Rowing races were rescheduled for later in the week, while Monday's events were moved to Sunday in anticipation of the storm.
The rain also threatens Tuesday's two medal games for softball.
Canada, vying for bronze, said their flights home are scheduled for Wednesday with the next available potentially not until Saturday because the pandemic has limited travel options.
The storm is forecast to pass to the north of Tokyo, according to the Japan meteorological agency.
Australian Associated Press