Okra (warm-season pod vegetable) is classed very tender 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
Start seeds indoors
12 days before to 2 days after the median last spring freeze
Sow in pots 4–6 weeks before the outdoor window opens (Missouri G6570: 4–6 weeks, sown directly in pots).
Transplant outdoors
30–44 days after the median last spring freeze
Same outdoor timing as direct sowing; Missouri G6570 notes okra transplants are pot-grown to avoid root disturbance.
Direct-sow outdoors
30–44 days after the median last spring freeze
Purdue: very tender — at least two weeks after the last frost; Penn State's earliest sowing May 31 (+30 days for a May 1 frost) is the later start and is used. Okra wants thoroughly warm soil.
Seed germination soil temperature: optimum 95°F (optimum range 70–95°F); minimum 60°F, maximum 105°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 variety (about 55–65 days from seed; Penn State lists 55).
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.
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.