Tuner's Logger / Instrument Climate Service

Piano Interior Forecast

Rack East — Hall A, Llanfair-on-Wye
Issued 13:42 local · 14 March 2026
Valid 14:00 through 22:00
Pitch Drift Advisory — Upright Interior Bulletin 026-A · 13:42

In effect 14:00 through 22:00. Single-instrument scope.

Soundboard moisture content rising 0.4% per hour. Projected A4 deviation at 19:30: +3.8 cents sharp, mid-register, with treble bridge lag of approximately 1.2 cents. Threshold for concert-grade stability (±2 c) exceeded by 16:10. Crown loading non-uniform; unisons expected to spread 1–2 c by curtain. Re-tune window closes 17:30 if hall HVAC engages on schedule.

Current Conditions · Lid Interior, Treble Side · 13:42

Interior RH
56%
+13 since 08:00
Soundboard MC
9.4%
rising 0.4 / hr
Case Dew Point
10.1°C
case lag ~90 min
A4 Projected · 19:30
+3.8c
mid register, sharp

Hourly Trace · Interior RH & Soundboard MC · 13:00 – 21:00

42% — LAST TUNED 50% — ADVISORY ZONE 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 19:30 CURTAIN 40 44 48 52 56 60 INTERIOR RH (%) 7 8 9 10 11 SOUNDBOARD MC (%)
Interior RH  left axis, percent Soundboard MC  right axis, percent
Sensor: lid interior, treble side Sampling 5 min / smoothed hourly

A4 Pitch Deviation Forecast · cents from 440.0 Hz

+6 +4 +2 0 -2 CENTS FROM A440 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 +2 c — CONCERT THRESHOLD -2 c — CONCERT THRESHOLD 19:30 CURTAIN +3.8 c
Forecast A4 deviation Concert threshold  ±2 c Band  ±1.5 c confidence
Reference: A4 = 440.000 Hz at 20.0 °C Model: spruce response, 90-min case lag