A slow-moving cold front interacting with residual tropical moisture from the remnants of Cyclone Rachel is the main driver of current Polymarket odds for measurable precipitation on October 13, 2026. National Weather Service and NOAA guidance indicate widespread showers and thunderstorms across the Northeast, with Boston, MA, showing near-certain rain chances and high probability of accumulation exceeding measurable thresholds. The Central and Southern Plains face elevated storm risk along a dryline, supporting moderate odds for cities like Chicago and Houston, while model consensus points to 2–3 inches possible in corridors from western Missouri to Texas. Drier conditions dominate the West Coast and Southeast, keeping implied probabilities low there. Traders are monitoring the latest NWS short-range forecasts and any overnight model shifts ahead of Tuesday’s resolution criteria based on official station measurements.