Peas (cool-season legume) is classed hardy in the cited extension guidance. The timing rules below are relative to your local freeze dates — enter a location to turn them into calendar dates.
The rules this site applies
Method
Frost-relative window
Rule & reconciliation
Direct-sow outdoors
6–4 weeks before the median last spring freeze
Purdue: hardy — plant 4–6 weeks before the last spring frost. Penn State earliest sowing Apr 1 (−30 days) sits inside that range; UNH says as soon as soil thaws.
No start seeds indoors window: Peas are direct-seeded; transplanting is not part of the cited timing guides.
Seed germination soil temperature: optimum 75°F (optimum range 40–75°F); minimum 40°F, maximum 85°F. Purdue HO-186-W Table 3. Cold soil below the minimum rots seed — a reason windows and soil readings both matter.
Variety assumption: Assumes an average shelling/snap variety (about 60–70 days; Penn State lists 65).
Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.
Earliest/latest sowing dates for a May 1 last-frost / Oct 1 first-frost baseline; offsets derived by date difference from May 1. Also days-to-maturity figures.