A father-of-three will ascend the highest mountain in south Wales for the 365th time in a year on Saturday.
Des Lally, 43, a mortgage broker from Brecon, has been walking up and down Pen y Fan in the Brecon Beacons on most days for the last year.
He has braved blizzards, 5ft (1.5m) snow drifts, 80mph winds and countless torrential downpours in aid of charity.
Heat exhaustion last summer left Mr Lally facing a number of ascents each day as he makes up lost time.
"The toughest side is definitely the mental side," he explained.
He has raised more than £40,000 for Help for Heroes, a charity which helps injured or unwell former military personnel, and Cancer Research UK.
Mr Lally said both charities meant a lot to him personally - his father served for 25 years in the Army, and both his parents have been affected by cancer - which provided all the motivation he needed.
"When you are turning up at nine at night and it's dark, there are 70-80mph winds, it's smashing down with rain, you are on your own and I think 'here we go again'," he said.
"But you have only got to think about the reasons you are doing it and you are soon out of the car and on the way."
He has faced numerous challenges along the way; from the searing heat and biting cold, to injured ankles and twisted knees.
On Friday, Mr Lally made the 500m ascent from Storey Arms to the summit of Pen y Fan three times in order to leave himself one final climb on Saturday.
"It has been awesome," he replied, asked how he felt with a handful of ascents remaining. "I have loved every second of it."
Mr Lally said he expected to set off for the summit at 11:00 GMT, and arrive back at Storey Arms at 13:00.