Peppers really need warmer temps, they’ll get stunted in the 40s. Memorial Day weekend is when I put the peppers out and I have them outside during the day from now until then.
I grow at least 10 varieties a year and do very well. I kept trying to put them out in May bc I’d get fooled by warmth - but until Memorial Day the risk of 40s overnight (and cold rains!) have not passed. Cold temps for young pepper plants is very damaging.
Tomatoes aren’t far behind, but I’ll put those out in mid-May, even when it’s a cool May like this one.