“I thought it was a bit warmer than it was,” explained the 32-year-old former St George-Illawarra Dragons and Cronulla Sharks front-rower.
“When I realised how cold it really was, I just decided not to bother getting changed.”
Arriving from the heat of a Sydney summer – where the thermometre topped out at 40 degrees yesterday – Prior has much to adjust to, on and off the field.
He was signed in November after marquee recruit Trent Merrin returned to the NRL with St George.
Family issues condemned Merrin to a difficult 12 months at Leeds and he never seemed fully settled, despite making a big impact in Rhinos’ ultimately successful battle against relegation.
Leeds will be hoping for better fortune with Prior and the player himself, who has travelled with partner Rebecca and daughter Indie, is clearly relishing a fresh start and new challenge.
For Prior, this is a first stint in Europe at the back end of a career which has seen him accumulate more than 250 NRL appearances, plus a State of Origin cap for New South Wales in 2018.
“I’m very excited to be here,” said the forward, who won an Australian Grand Final with each of his previous clubs.
“Leeds is a lovely town, a lot bigger than what I was expecting.
“We are starting to settle in now and glad to be here.
“It is a great club, a club that’s had a lot of success in the past.
“They are looking for more success and I want to be a part of that.
“I don’t know that much about Leeds, but I am looking forward to learning everything about the club.”
Leeds coach Richard Agar has long been an admirer of Prior, who will wear the number 10 jersey this year.
Merrin’s exit opened a space on Leeds’ overseas quota and Prior said: “My manager spoke to me and said they [Rhinos] enquired about me and asked if I’d be keen to come over.
“I met Rich in Australia when he was out there, we had a brief chat and it snowballed from there.
“I don’t know that much about Leeds, but I am looking forward to learning everything about the club.
“I always wanted to come over here and play a couple of years and it has all worked out really well.
“I am happy to be here, it is very exciting times.”
Rhinos have left two vacancies in their squad for more recruits, though their ability to bring in another import hinges on Australian-born forward Rhyse Martin being granted a Papua New Guinea passport.
With 33 of the club’s 36 full-time players being under the age of 30 when the season begins, Prior’s experience will be much-needed.
In turn, he feels Super League’s less structured playing style, compared to the NRL, will suit the way he likes to play.
He said: “Everyone says Super League is really fast, a bit faster than the NRL and they like to play a bit more footy than the NRL.
“There’s a lot of teams that are very structured in the NRL, with a defence-oriented mindset and I guess it’s a bit more free-flowing over here.
“I am looking forward to that side of it. Everyone has said how good the crowds are and how passionate and how into the games they get. I am looking forward to that as well.”
Of what Leeds can expect from him, he added: “I will bring plenty of energy on the field.
“I’ll try and lead by example and do all the little jobs and do whatever the team needs, really.
“I guess I am a bit of a team man, I will be out there trying to put my best foot forward for the boys and lead by example is the main thing.”
Prior will train with his new team-mates for the first time tomorrow, before jetting to Spain for a warm-weather training camp on Sunday.
Though he has just a month to prepare for Leeds’ first competitive game, he insisted he will be ready.
“I kept training with the Sharks, just to keep fit,” he revealed. “They were happy for me to keep training so I’ve done a whole pre-season with those boys.
“I think, to learn all the plays and stuff, a month is plenty of time. I am looking forward to the camp, [I’ll] get around all the boys and get to know everyone and start trying to fit in among the group.”