Sir Ranulph Fiennes is at the final camp before Everest's summit in his attempt to conquer the world's highest mountain.
Sir Ranulph is expected to take 10 hours on the final push
There had been fears that bad weather would force his team to abandon the record attempt.
But a call via satellite phone confirmed on Friday that the Jagged Globe team had reached Camp 4.
This stands at 8,400m (27,560ft) and is the last stop before the final 10 hour push to the 8,850m (29,035ft) summit.
The team, moving as two groups for safety, are taking the more hazardous North Ridge route.
The first group has already reached the top, but the one containing Sir Ranulph is expected to make an attempt on the summit at about 11pm local time.
Expedition spokesman Tom Briggs said: "The first team is equipped with vastly superior oxygen masks so they made the the summit very quickly.
"But we expect Ran's team to make the climb more quickly than most teams so we think it will take them about 10 hours."
If the attempt is successful, Sir Ranulph, 61, will have raised about £2m for the British Heart Foundation.