Cilantro (cool-season annual herb) is classed semi 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
4–2 weeks before the median last spring freeze
Oklahoma State: sow two to four weeks before the last spring frost (with a second sowing in late summer for fall harvest). Cilantro bolts in heat — sow early.
No start seeds indoors window: Cilantro is tap-rooted and resents transplanting; the cited guide times direct sowing only.
Variety assumption: Leaf harvest begins about 40–50 days from sowing; bolts quickly in warm weather.