The Tigers have made a blistering start to their Betfred Super League campaign with four straight wins but Powell knows it would be a tough ask for them to maintain their high standards throughout the year.
"Without question, we're going to have tough times throughout the year," Powell said. "I don't think anybody would expect to go through a season without having a difficult period.
"We've just got to be as consistent and as mindful of the challenge ahead of us every single week and I think we have done that well so far."
Powell's men have emerged from their first four fixtures as the form team of the competition and their next block culminates in an eagerly-awaited trip to Wigan Warriors, the only other unbeaten team, but the coach insists that game on April 6 is not on his players' minds just yet.
"We're enjoying ourselves at the moment," Powell said. "But we need to recognise we've got some tough games coming up. We've just gone through our first block of games and we've done really well and it's about putting those behind us and moving on.
Here's a reminder of Sunday's squad if you missed it this afternoon 🏉 pic.twitter.com/hH4LJZaOPH— Castleford Tigers (@CTRLFC) March 17, 2017
"I always talk about not getting too far ahead of ourselves. You try and forearm the players but I wouldn't have thought any of them would be looking at the Wigan game.
"I am not. You might look a little bit at it from a coaching perspective in terms of a bit of proactive planning but this is the game that's in front of us."
Castleford could come up against former State of Origin stand-off Todd Carney, who has been included in Salford coach Ian Watson's 19-man squad for the first time and is likely to start on the bench for his first match for seven months.
"There's a bit of an unknown with Todd Carney but their half-backs have been playing really well anyway," Powell said.
"They're a good side, Ian Watson has done a good job there. They challenge you, they shift the ball wherever they are on the field so there are some similarities with ourselves."
Watson, who has guided his side to two wins from their opening five matches, is looking forward to seeing them go up against the rampant Tigers.
"I'm really looking forward to the Cas game," he said. "They play great football, as do we."
In Sunday's other game, Wigan defend their 100 per cent record against Huddersfield Giants at the DW Stadium.
The Giants are coming off the back of consecutive heavy defeats by Hull FC and Leigh Centurions and coach Rick Stone knows his side will need a vast improvement if they are to halt the reigning champions.
"It's a good opportunity and a good challenge," Stone said. "Wigan are a tough team and are one of the powers of Super League and they have always been up there.
"It's a good challenge for our blokes to go there and hopefully the boys that played last week who were on the fringe of fitness will be a bit more comfortable this week, and our team will be stronger because of that.
"Wigan are tough, aggressive and really committed defensively. There are a couple of things we can have a look at but trying to match them physically is our first call."