DHT22 humidity sensors equilibrate with surrounding air after power application. Temperature responds faster; humidity may drift toward true values over several minutes—especially if the sensor was stored in a cold truck before install. Firmware and installers should ignore or flag early samples so JSON and LCD do not alarm on transient RH.
Boot behavior
Skip publishing humidity for the first **one to three minutes** after reset, or mark reads as warming in serial logs via serial debug. Align with main loop timer so HTTP still serves temperature if needed.
Environmental triggers
- Cold snap after warm storage—humidity lags real air.
- Door event mixing humid outdoor air—wait one poll cycle before alerts.
- Vehicle heat nearby—see stored vehicle heat.
User-facing impact
Dashboard history inherits warm-up blips if inserts run immediately—pair with retry policy and condensation basics for interpretation, not panic.