I usually plant peas on, or close to, St Patrick's day.
If they don't make it I just replant later.
I find they do better if I can get them going before the heat hits.
I'm in Colo Spgs

Peas can be tricky here because to be productive they need to be started around St Paddy's day but we can get late freezes. Last year most of my peas died in the April cold snaps

It's important especially with clay soils that soil temps are high enough that the pea seed doesn't rot before germinating.

Snow usually isn't bad for cold weather veges because it can act as an insulator.

I started my peas in a tunnel and they seem to be doing ok.

On a walk in Central Denver yesterday I saw a house with a wall of old rusty bed headboards in newly worked soil and a proud "Peas" sign staked at the end; someone has decided to go ahead. What have you got to lose?