England monthly dry-to-wet rainfall transitions showed no clear increase between 1901-1962 and 1963-2024

We tested whether England dry-to-wet next-month rainfall transitions increased beyond changes in separate tail frequencies. We used Met Office monthly rainfall, calendar-month 20th and 80th percentiles fitted in 1901-1962, and 682 within-year month pairs per era. There were 27 transitions in 1901-1962 and 28 in 1963-2024. Frequency rose from 3.959% to 4.106%, a change of 0.147 percentage points. The conditional 95% five-year block interval was -1.613 to 1.906 points. After adjustment for separate tail frequencies, the excess change was 0.173 points (-1.263 to 1.561). All planned sensitivity intervals included zero. The result gives no clear increase for this scale and event definition. It does not establish equal risk or test local floods, river flow, or drought recovery. One national series, a selected period split, omitted year-boundary pairs and conditional uncertainty limit inference. We provide a credited adapted input table, code, all estimates, bootstrap draws, a figure and an independent exact count audit.

rainfall · England · dry-to-wet transitions · whiplash · marginal frequencies · null result · block bootstrap