Having survived a challenging ascent of Denali earlier this month, an Australian man has moved on to Everest Base Camp in the Himalayas, where he has a little more than a month to reach his goal of scaling the world's Seven Summits faster than anyone in history.

Steve Plain of Perth reached Denali's 20,320-foot summit April 3 with climbing partner Jon Gupta of Caernarfon, Wales. Part of a four-man climbing crew, Plain and Gupta made a 20-hour push from their camp at 14,000 feet to the summit and back, reaching the top a little before 10 p.m.

Theirs was the first successful climb of the season at Denali, according to the National Park Service. Last year's first summit came on April 21.

For Plain, 36, it was his sixth successful expedition since January. In a three-month span beginning with a Jan. 16 summit of Antarctica's Mount Vinson and ending with the Denali climb, he has climbed the tallest peak on six of the world's seven continents. All that remains in his quest is Asia's Mount Everest.

By Tuesday — three weeks after he and Gupta stood atop Denali — Plain had reached the Everest Base Camp. If he can reach the top of the 29,029-foot mountain before May 22, he will break the Seven Summits speed record set last year by Poland's Janusz Kochanski, whose effort stretched from Jan. 14 to May 20.

Plain is climbing for a cause. In December 2014, he broke his neck in a surfing accident and was told he might never walk again. When he recovered from his injuries, he decided to raise money for some of the charities that helped him after his accident. He's calling his effort Project 7in4 — seven summits in four months.

So far, Plain has climbed, in order, Mount Vinson (16,050 feet), South America's Aconcagua (22,841), Africa's Kilimanjaro (19,341), Australia's Carstensz Pyramid (16,024), Europe's Mount Elbrus (18,510) and North America's Denali.

In a Facebook post chronicling his adventures, Plain said Denali was the most grueling and frightening climb so far. Temperatures hit minus-40 on summit day, which Plain described as "one of the toughest days I've ever had in the hills."

"The feeling is strange. I am not excited, I am not thrilled, I am not even relieved. I am glad it's done but know we still have a few more days in this inhospitable environment until we are back to civilisation and can then reflect on what we just achieved.

"… Jon and I set out from 14k Camp on our summit attempt at 09:15. We initially went back up the headwall, climbing made easier with the aid of fixed ropes we set a few days ago. From there on we were on new terrain.

"At 17k Camp we stopped for a break and quick gear change. …. We initially got quite hot in the midday sun but as we traversed "The (Autobahn)," rounded "Denali Pass" and continued onto the upper slopes our down suits were a godsend. Although to give you an idea of the temperature, I had a water bottle in a chest pocket INSIDE my down suit which froze solid by mid afternoon. And there was our biggest challenge, it was so cold all our water froze. We were getting dehydrated and consequently our progress slowed with the altitude. It became a real struggle.

"It was 21:45 by the time Jon and I took the final steps to the summit. The glow of the setting sun on the horizon was spectacular but incredibly daunting. We had pushed very hard to get to the summit and still had a very long, cold night ahead of us until we were down safe.

"With temperatures dropping below -40 deg C, dehydrated, fatigued, and descending very exposed terrain, we were tested all night. It was 05:00 by the time we finally stumbled back into camp, a grueling 20hr round trip. We got out of all our frozen gear and collapsed in our tent. Epic."

Plain and the rest of the team were picked up and flown to Talkeetna on April 6.

No one has summited the peak since, and no climbers were on Denali on Monday, the National Park Service said.

The climbing season is just now gearing up, spokeswoman Maureen Gualtieri said in a press release, with a few teams scheduled to arrive later this month and the bulk of climbers arriving in early May.

She said 743 climbers are registered to climb Denali this season, although typically that number grows once the season starts. Last year, 1,289 people attempted the climb and 495 made successful summits, according to the National Park Service's 2017 mountaineering report.