Alerts & Notifications

    Hysteresis band explained

    Lemwatch requires response time to fully clear a threshold before recovering, preventing oscillation alerts.

    Updated 2026-07-09
    1 min read
    hysteresis
    thresholds
    accuracy

    Quick answer#

    If your alert threshold is 2000ms, Lemwatch won't mark the site "recovered" until response time drops below 1600ms (2000 − 20% band). This stops jittery pages toggling between degraded and healthy.

    What it does#

  1. Adds a 20% clearance band below every threshold
  2. Requires the metric to fully cross the band before flipping status
  3. Applies to response time, TTFB, LCP, INP, and health score
  4. Prevents "recovered → degraded → recovered" alert loops

    5. Where to find it in Lemwatch#

    Site → Settings → Alert accuracy → Hysteresis band.

    How to tune it#

  5. Open the site's Alert accuracy settings.
  6. Adjust the Band width (default 20%) — wider = more stability.
  7. For very stable sites, drop to 10%.
  8. For noisy sites near threshold, raise to 30%.
  9. Save.

    10. FAQ#

    Does this delay recovery alerts?#

    Only when the metric hovers right at the threshold. Clear recoveries fire immediately.

    Does it apply to uptime status?#

    No — uptime is binary. Hysteresis is for continuous metrics.

    Related#

  10. Response time thresholds
  11. Flapping detection
  12. Why am I getting false alerts?
    13. Was this article helpful?

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