Direct answer
Because How pressure and wind angle push rain into joints that remain dry during calm vertical rainfall. The pattern becomes meaningful only when it repeats with the same trigger, delay and location; one isolated observation cannot identify the underlying condition.
Why this question matters for Wind-driven rain signatures
How pressure and wind angle push rain into joints that remain dry during calm vertical rainfall. In the wider path, the observed clue is a ceiling or wall stain that appears after weather A good answer stays tied to the actual sequence instead of converting a familiar pattern into a diagnosis.
What to compare
Compare roof or flashing entry, wind-driven wall entry, plumbing leakage and cold-surface condensation and ask which one predicts the observed delay and geometry. The main lookalikes remain roof or flashing entry, wind-driven wall entry, plumbing leakage and cold-surface condensation.
A useful evidence record
Write down the exact location, date and time, weather, equipment or water-use state, recent changes and one unaffected reference. Preserve photos before wiping, opening, repainting, tightening or resetting anything. State uncertainty directly.
How the answer changes the next step
If the result strengthens one pathway and weakens another, continue to the matching safe-check or scope guide. If both explanations remain plausible, repeat under controlled conditions or prepare a professional handoff rather than choosing a repair by guesswork.
Safety boundary
Do not enter an unsafe roof, open energized assemblies or disturb damaged materials. Active dripping near electricity, sagging finishes or structural movement requires prompt professional assessment. HouseSymptoms provides information and documentation structure; it does not certify a diagnosis or authorize regulated work.
