The 31-year-old windsurfer is at the Games venue this week – the Weymouth and Portland National Sailing Academy – looking to retain his title from last year.
And he certainly is well placed to do so after day three, sitting second overall and heading into Thursday's action with a victory in his last race.
Sitting atop the RS:X men's standings is Julien Bontemps, the Frenchman fresh from claiming the world title in March in Cadiz, where Dempsey was forced to settle for silver.
But while Dempsey is keen to reverse that result from Spain at Sail for Gold this week, he is just as happy to experience all that Weymouth can throw at him ahead of his return for the Games in two month's time.
"The regatta has been okay so far," he said. "It's often tough at the beginning of the week as all you really want to do is stay in the game and not really make any big mistakes and I had managed to do that until the first race on Wednesday where I finished 13th.
"It has not been too bad, I think a few other people have got some big numbers, so it has been good and we have a good forecast for the rest of the week so I'm looking forward to it.
"But it is fantastic to experience all the different conditions because we had light winds on Monday, we had the south-easterly direction wind after that and here we were out in the bay so it is kind of mixing it up and throwing everything at us and a perfect test for the Games.
"I learn something everyday. The first race here I thought the wind was going to be slightly different to how it was and it can easily catch you out so you never know at all.
"It is so much about learning this event, and putting everything into practice. It constantly throws everything at you."
Elsewhere, Stevie Morrison and Ben Rhodes sprung into life in the 49er, finishing first and second twice in Wednesday's three races to move up to fourth overall, one play behind compatriots Dave Evans and Ed Powys.
The Finn class saw a real Battle of Britain take place and Giles Scott now leads the overall standings, leapfrogging Ben Ainslie into top spot.
In the 470 men's, London 2012 duo Luke Patience and Stuart Patience sit third overall after finishing both races in third, while in the women's class Hannah Mills and Saskia Clark slipped from first to third after a disappointing day.
However there was plenty to celebrate in the Star as Iain Percy and Andrew Simpson climbed to the top of the leaderboard with finishes of second and first, while Paul Goodison also moved up the Laser fleet and now sits sixth overall after two second-place finishes.
Alison Young's fourth and second-place finishes sees her sit fifth in the Laser Radial while the match racing team qualified for the gold group in first with ten victories from 12 rounds.
In the Paralympic classes, Great Britain's Sonar team are also top while Paralympics-bound Helena Lucas is now third in the 2.4mR competition.
Meanwhile, Alexandra Rickham and Niki Birrell picked up from where they left off as they won both of their Skud 18 races to consolidate their position atop the standings.
But with plenty of the regatta still to come, Birrell is vowing not to ease up on his rivals any time soon.
"We had an OK third day," he said. "We did two races and we managed to get two wins so that means we have got five wins and a third from the first six races so so far so good.
"But there are still four races to go and we want to be in the same place we are now at the end so there is still plenty to do."
