This study examines the spatiotemporal variability of summer monsoon precipitation in Pakistan during 1979-2024 and its implications for cropland exposure. Using station observations and nonparametric statistical methods (Mann-Kendall, Sequential Mann-Kendall, and Sen's Slope), we quantify sub-seasonal trends and explore potential climatic drivers. Results reveal a clear sub-seasonal redistribution: precipitation increases in June and September (up to similar to 1.07 mm yr(-)& sup1;) and decreases during the peak monsoon months, particularly August (down to - 1.58 mm yr(-1)). Spatial patterns indicate a westward redistribution of precipitation intensity from humid to semi-arid regions. Cropland exposure, defined as the product of precipitation and cultivated area, remains concentrated in the northeastern agricultural core, with peak values exceeding similar to 2500 km(2).mm in July, while extensive rainfed croplands in arid western regions receive minimal exposure. This spatial mismatch highlights increasing hydroclimatic vulnerability. Decomposition analysis shows that increases in exposure to C3 crops are primarily driven by cropland expansion, whereas climate variability contributes more strongly to C4 crop exposure. Composite analysis reveals that wet (dry) monsoon phases are associated with enhanced (suppressed) low-level moisture transport, higher (lower) relative humidity, and increased (reduced) cloud liquid water content under cyclonic (anticyclonic) circulation anomalies. At the same time, large-scale modes (ENSO, IOD) exert a comparatively weak influence. These findings demonstrate that Pakistan's agriculture is increasingly sensitive to sub-seasonal monsoon variability, underscoring the need for region-specific adaptation strategies.