McGinn took his tally to 11 for the season with goals after 63 and 81 minutes as the Dons defied incessant horizontal rain to end a three-match winless run and climb to fourth, above Saints, who are without a win in four.
"The conditions were farcical today," Lomas said. "I don't want it to sound like sour grapes but that wasn't a game of football.
"The wind spoiled it as a spectacle and I feel sorry for any fan that had to pay. I didn't enjoy one minute of it. I don't know about summer football but there have to be measures taken."
Asked about Lomas' belief the match should not have gone ahead because of the conditions, Aberdeen boss Craig Brown said: "No, because of the result. I'm joking. I know Steve and I think if he had won he would've said the same. The conditions were poor for both sides and they coped admirably. Considering the conditions it wasn't a bad game."
The Dons were profligate in the first half, with McGinn twice denied by Alan Mannus, before the Northern Irishman scored from a free-kick and then added a second.
McGinn was linked with St Johnstone, but Lomas conceded the Perth side could not compete with Aberdeen for his signature. McGinn and the Dons might have scored more, particularly in the first half when Mannus made a point-blank stop from his compatriot at close range.
Brown added: "I ran out of counting how many saves the keeper had. We had a lot of good chances today. The only worrying thing is we had so many chances and we didn't get more goals.
"Niall McGinn side-footed it and turned away to celebrate the goal. All of a sudden he found that it was a save. We've not been playing badly. We've had dominance of games, but it hasn't been reflected in the score. Today it was.
"In fact, I think we should've scored more. I'm pleased for the fans, pleased for the team. Without question we were the better team."