Only 9.1 overs of play was possible in Whangarei before the match was abandoned with no result, the home side having reached 70-1.
All-rounder Stuart Broad, who missed the limited overs tour of India with a heel injury, returned to captain the side and took a fine catch to remove Hamish Rutherford off the bowling of Chris Woakes for 21.
However, Knight told Sky Sports News that neither Broad nor his fellow seamers were particularly impressive with the ball.
"Broad didn't bowl brilliantly - he bowled a little bit too short as England's seamers did on a surface that was helpful, so he'll be a little bit disappointed with that," reflected Knight.
"But let's be brutally honest, it's been raining throughout the last few days. It's damp - it's not brilliant conditions. It's slippery underfoot.
"So let's just give them a little bit of leeway. They'll know they've been a fraction short. Stuart himself will know that he's been a fraction short and it's not a brilliant performance first up."
England named both Jos Buttler and Jonny Bairstow in their line-up but asked the former to keep wicket and Knight feels the Somerset man will now keep the position for the upcoming T20 series against New Zealand, which begins on Saturday at 5.30am on Sky Sports 1 HD.
"My gut feeling is that Bairstow is the better option moving forward. But England have made a call - they are going to go with Buttler.
"I assume that having gone with him in this game that they are going to give him the next couple of opportunities in these warm-up games.
"Whether they change and give Bairstow a chance would be surprising now that they've gone with Buttler. So their intentions are quite clear.
"For now Bairstow will play anyway as a batter. But when Kevin Pietersen comes back into the side that makes it a little more tricky to get everyone in. So a big decision's been made and good luck to Buttler."
Watch the first T20 international between New Zealand and England live on Sky Sports 1 HD from 5.30am.