Once a bad measurement lands in Home Assistant's long-term statistics, it stays in every graph built from them. For totals such as energy there has long been a way out, the "Adjust sum" tool. For mean statistics, such as temperature, there was none: the values cannot be adjusted, so the only fix was to delete the whole statistic, with its entire history. Two changes by Paulus Schoutsen, merged on 14 and 15 October 2026, let you cut out just the faulty period instead.
A new button in the statistics table
The frontend change (#54875) adds an icon button to every row of the statistics table, on the Statistics tab under Settings > Tools. It opens a dialog called "Delete statistics in a time range". You pick a start and an end time; by default the range covers the last 24 hours.
Before anything is deleted, the dialog draws a chart of the data in the selected range, so you can see whether the spike you want to remove is really in it. Ranges of up to three days are previewed with the 5-minute short-term statistics, longer ones with hourly statistics. Short-term statistics are purged earlier than hourly ones, so if the 5-minute data for a short range is already gone, the preview falls back to hourly data. The dialog also warns that deleted statistics cannot be restored.
What happens underneath
The Core change (#186071) extends the recorder/clear_statistics WebSocket command with two optional fields, start_time and end_time. They have to be sent together and the end must come after the start; otherwise the command returns an error. With a range, Home Assistant deletes only the rows that overlap it, in both the short-term and the hourly table, and keeps the statistic itself along with everything recorded outside the range. Without a range, the command works as before and removes the whole statistic.
This is a delete tool, not a correction tool. The selected period loses its data; nothing is recalculated or replaced. To fix a wrong value in energy and other cumulative statistics, "Adjust sum" is still there.
When
Both changes are in the development branches, where Core is at 2026.11.0.dev0, and neither is assigned to a 2026.10 patch release. The feature should therefore arrive with Home Assistant 2026.11. Until then, the only way to get rid of a bad reading in a mean statistic from the UI is still to delete the statistic completely.