Nine of 23 winter rainfall deficit closures reversed in three British countries in 1910-2024 under 1961-1990 means

We tested whether a first monthly rainfall deficit closure remained in place through March. We used Met Office rainfall for England, Wales and Scotland. We selected the driest fifth of April-September seasons in 1910-2024 and tracked monthly anomalies from fixed 1961-1990 means. Of 69 dry country-seasons, 23 cleared the deficit at least once during October-March. Nine later returned below zero. The reversal fraction was 39.1%, with a conditional 95% five-year block interval of 15.4% to 64.3%. Seven crossings ended March negative. The nine reversals span six distinct years. With 1991-2020 means, only 12 paths crossed and two reversed. A synthetic reordering of winter anomalies gave a similar ratio of expected counts, 37.9%. The evidence does not require an unusual physical timing process. A later +10 mm closure-margin check gave four reversals among 18 crossings. This study gives a monthly path audit and shows strong reference-period sensitivity. It does not measure water-store recovery or prove a general reversal rate. Small counts, shared weather, fixed means, monthly sampling, source revisions and conditional uncertainty limit inference. Code, inputs, provenance, paths, draws, an audit and a figure are included.

rainfall deficit · temporary recovery · England · Wales · Scotland · reference period · monthly paths