"We trained around midday today and it's definitely warm, but humidity has a big part to play in fatigue and feeling lethargic, and there hasn't really been that here.
"It's been hot, no doubt about it, but we've had some pretty good weather back home at times too."
Warriors coach Stephen Kearney refuses to make an issue out of the hot weather publicly, but the players have been sighted wearing extra layers at training throughout the pre-season, and several industrial furnace heaters were brought inside to make their gym sessions more taxing.
Johnson believed such methods were effective in helping the players to train harder, but was unsure if it would prepare them sufficiently for 80 minutes of football under the hot sun.
"Yes and no, I'm not too sure," he said.
"I don't think you can match actual heat but we've had good weather back home and during that weather we threw on a few layers, long skins, and a couple of contact jackets, and you sweat up and you do feel it.
"Whether that's going to be all we need for this weekend's game, we'll see."
Despite the hot weather, there are some benefits to the Warriors playing in Perth in round one rather than mid-season.
With no match last weekend they were able to travel across the Tasman and begin acclimatising and adjusting to the five-hour time difference earlier than they have in previous years.
"Usually we come here two or three days before but we're here for the whole week this time," he said.
"We're just trying to acclimatise as best we can, it's pretty warm here, and with the time difference as well.
"Maybe that's something we've struggled with, who knows, but in terms of fitness and the preseason, it's been a good one and the boys are excited to play."
The players enjoyed some extra leg room in premium economy seats during their flight over, but Johnson was pleased the coaching staff did not go overboard in trying to manage the players over the last 48 hours.
Keeping their fluids up was a given for professional footballers, and the onus was on the players to take a common-sense approach to their health and well-being.
"They've been pretty relaxed. Sometimes with these situations you can give someone too much information and overthink things but they've done things subtly.
"They got us out of the hotel at 7pm last night just to get us moving, and we had our usual pool recovery when we arrived and we were up with an early start today.
"They haven't treated us like kids and they've given us the responsibility of hydrating which they briefly mentioned to us, along with staying active, and making sure that we got a good night's sleep.
"They're doing their bit and we've just got to do ours."
The Warriors have another training session today and will cap their preparations with a captain's run on Friday.
Rabbitohs v Warriors at Optus Stadium, Perth - Saturday, 9pm (NZT)
Rabbitohs: 1. Alex Johnston 2. Richard Kennar 3. Dane Gagai 4. Greg Inglis 5. Robert Jennings 6. Cody Walker 7. Adam Reynolds 8. Thomas Burgess 9. Damien Cook 10. Mark Nicholls 11. John Sutton 12. Angus Crichton 13. Sam Burgess.
Interchange: 14. Cameron Murray 15. Tyrell Fuimaono 16.George Burgess 17. Tevita Tatola 18. Robbie Farah 19. Jason Clark 20. Hymel Hunt 21. Adam Doueihi.
Warriors: 1. Roger Tuivasa-sheck 2. David Fusitua 3. Peta Hiku 4. Solomone Kata 5. Ken Maumalo 6.Blake Green 7. Shaun Johnson 8. James Gavet 9. Issac Luke 10. Adam Blair 11. Isaiah Papalii 12. Tohu Harris 13. Ligi Sao.
Interchange: 14. Sam Cook 15. Leivaha Pulu 16. Sam Lisone 17. Bunty Afoa 18. Jazz Tevaga 20. Mason Lino 21. Agnatius Paasi 22. Anthony Gelling.
Referees: Grant Atkins, Jon Stone.
The Warriors' Awful Record in Perth
1996: Lost 32-12 to Western Reds at the WACA
1997: Lost 24-12 to Western Reds at the WACA
2005: Lost 28-24 to Cronulla at nib Stadium
2012: Lost 24-22 to Manly at Subiaco Oval
2013: Lost 30-13 to South Sydney at nib Stadium
2014: Lost 34-18 to South Sydney at nib Stadium
2015: Lost 36-4 to South Sydney at nib Stadium
2016: Lost 15-14 to Manly at nib Stadium
2017: Lost 26-22 to Manly at nib Stadium
