I think heat would be the enemy around here. We’ll get 100-degree highs any time from April into October, but June and July can easily top 110 on any given afternoon and it hits 117 or 118 some days.
The worst freezes are usually in January, maybe two or three consecutive nights into the low twenties. Last touch of frost sometime in late March or early April, generally just after I plant peppers.
In Colorado I planted as soon as the ground thawed out. You could probably plant a month before the last frost and use early or main harvest varieties so they mature before it gets too hot.