All gardening is local.
I grew up hearing that peas and potatoes (and spinach and lettuce and carrot seed) needed to be planted between St Patrick's day and Easter, and the heat-loving plants go out on Memorial Day weekend. Where I live now, the heat-loving stuff doesn't go out until the snow melts off the "chickens," two high mountain valley meadows east of us (they look like folk-art chickens, or a chicken and a rooster) that face northwest and hold the snow until early May, sometimes later. I actually can't see the chickens from my yard (there's a mesa in the way), but I can from my step-dad's house.
Of course, the last couple of winters there hasn't been much snow, so the snow chickens are of less use any more.
Anyway, I have planted two plots of potatoes (blue flesh and yellow flesh/red skin), and still have the sprouted spuds from the pantry to put in. Yes, I do that, but I am the only gardener in the near neighborhood so I'm not threatening anyone else's garden. The only peas that got planted were the seeds that dropped because I didn't clean up last year's pea garden until Thanksgiving.
The carrots I grew for seed have seeded, too. But I really bought five more varieties of carrot, and I have radishes and lettuce and such that will go in this weekend.
My cute little tomato seedlings should be big enough to put out in early to mid May, but on the Memorial Day weekend at the latest, just like my mom taught me.
Catherine