Eukairos is the adjective describing what is timely, opportune, or well-seasoned — the kairos moment that is ripe for action. It appears in Mark 6:21 for Herod's 'opportune day' — his birthday banquet that gave Herodias her chance to demand John's head. In Hebrews 4:16 it describes 'grace to help us in our time of need' — the timely grace that arrives exactly when needed.
Hebrews 4:16 is one of the most comforting uses: 'Let us then approach God's throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need [eukairos boetheia].' The grace of God is not generic but perfectly timed — it arrives at exactly the right moment. This is the pastoral theology of divine timing: God does not give grace too early (before the need) or too late (after the crisis passes) but eukairos — right when it is needed. Every provision of God is well-timed.