"Pre-round snowball fight to see who has the honour off the first?" asked Donald on his Twitter site during the morning, while Kaymer was again wearing the snood he had put on for his semi-final against Bubba Watson as the temperature dropped.
"I woke up, drew the curtains and there was an inch or two of snow, but the sun's out and we're going to have a good day," added Donald.
Kaymer had worked much the harder of the two to reach the climax to the event, needing 20 holes to beat Justin Rose and then being taken to the 18th by Miguel Angel Jiménez in the quarter-finals and Watson.
Donald had yet to play the final hole and in his two previous games had seen off Ryan Moore 5 and 4 and then Matt Kuchar 6 and 5.
In all he had played 73 holes to Kaymer's 85, but it was less of a factor with the final being cut from two rounds to one this year.
Victory for Donald would take him all the way from ninth in the world to third behind Kaymer and Lee Westwood, but even if he lost he would move to sixth and equal his career-high.
Kaymer, who dethroned Westwood at the top of the rankings by reaching the final, was trying to make it five wins in his last 11 starts, a run that began with his first Major title at the US PGA Championship last August.
Donald had not been behind in any match all week and he struck first again with an 18 foot birdie putt on the long second.
Both missed the green at the next and Donald, having made a five footer for a half on the opening hole, preserved his lead from slightly longer.
The bad weather was not quite over - a hailstorm interrupted play on the fourth fairway.
Because it was hoped to be only a brief suspension Donald and Kaymer stayed out on the course rather than return to the clubhouse.
The delay was less than ten minutes and on the resumption Donald went two up, hitting his approach to three feet and then seeing Kaymer miss from nine once hailstones had been cleared from the path of his putt.
With conditions improving the German then drove into the desert scrub at the next, and after taking a penalty drop, a bogey five sent him three down after five with Donald getting up and down from a greenside bunker.
Kaymer had his first success when Donald three-putted the short sixth and a birdie on the par five eighth narrowed the gap to one.
In the all-American third place play-off, meanwhile, Matt Kuchar turned two up on Watson.