Climbing Mount McKinley in Denali National Park in Alaska usually is a goal that comes to fruition in May or June. Someone must have neglected to tell Lonnie Dupre that.

The Grand Marais, Minnesota, man not only summited the 20,237-foot mountain on Sunday, but he did it alone, a first in Denali's climbing lore.

"Today at 5:08 central time Lonnie Dupre reached the summit of Denali," read a post on his Facebook page.

The 53-year-old Dupre started his trek on December 18, when he reached basecamp. Three times before -- in 2010, 2011, and 2012 -- he had set out to accomplish the goal of standing atop McKinley, and each time he was forced back short of the goal by sub-zero cold and/or blizzards.

This year's effort, which won't be complete until he safely gets off the mountain, is fraught with both physical and mental challenges.

"I have currently been on the mountain for 21 days and I wanted to talk a little bit about the psychological difficulties you have on a trip like this," Dupre said in a voice message sent last Thursday from his satellite phone to his support team and published by the Alaska Dispatch News. "Mainly it is just the waiting for good weather so you can move. There is nothing worse than having to stay put, especially when you have 18 hours of darkness every evening; it makes for very long nights.

"And of course, always having the weather pull the rug out from under you when you were excited to go out somewhere that day and do some climbing. And then of course there is always worry about safety and supplies, and those kinds of things are the kind of things that weigh on my mind each day."