But it was a very rainy start to the event as a heavy shower came on half an hour before the women's race was due to start at 10am.
Security staff were sweeping away as much surface water as possible from the start route, under the arch at the entrance to Glasgow Green, where the race started and ends.
While riders, including Scotland's rising talent Katie Archibald from Milngavie can average speeds of 35-40mph, heavy rain can cause that speed to drop by around 10mph.
The time trial circuit - 40km for men, 30km for women - takes in Glasgow's East End as well as the countryside of East Dunbartonshire and North Lanarkshire.
Dozens of spectators arrived at Glasgow Green early to get the best view of the female cyclists whizzing round the Saltmarket after exiting the park.
Scotland and England flags stood side by side, pinned to the railings outside Glasgow's High Court.
Margaret Roberts, 73, from Carmarthen, in South Wales was there to support her granddaughter Amy, 19, who is competing for Wales.
She said: "I'm very excited and very proud. She has been cycling for about ten years. There's always an element of fear though watching her."
Steve Maddrell, 43, from Isle of Man said: "I'm here to support the Manx team as we'll the big riders including Geraint Thomas and David Millar, the home nations.
"I got here at 9am. We were at the Tour de France a couple of weeks ago so we knew to get here early. I think it will be great. The whole week has brought Glasgow to life. I'm just hoping the rain isn't too heavy, it can make a real difference to a cyclists time. It will be the ones who are prepared to take risks who do well."
In Sir Bradley Wiggins's absence, fellow Englishman Alex Dowsett will fancy his chances, having won silver in the event at Delhi 2010. Australia's strong road team includes national time trial champion Michael Hepburn, while defending Commonwealth champion David Millar is included in the Scotland line-up.
In the women's time trial, New Zealand's Linda Villumsen looks a strong prospect, having won silver in Delhi and medals at world level for each of the past five years, although time trial success depends on how the Glasgow course suits each individual rider.