A slow-moving frontal boundary and associated upper-level trough are driving scattered showers and thunderstorms across the Midwest, Ohio Valley, Mid-Atlantic, and Northeast on September 21, according to National Weather Service and NOAA outlooks. This setup, interacting with a moist, unstable air mass, supports the highest precipitation probabilities in those regions, with 60-90% chances in many areas and localized heavy rain risks, while the South and West see lower odds amid lingering heat or drier patterns. Short-term model consensus favors continued activity through Monday before the front shifts, though steering winds and instability details could adjust totals. Traders should watch updated NWS forecasts and radar trends for resolution thresholds tied to measurable rainfall at specific sites.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedWhere will it rain on September 21?
New York, NY
53%
Los Angeles, CA
24%
Chicago, IL
50%
Houston, TX
50%
Dallas, TX
41%
Phoenix, AZ
2%
Philadelphia, PA
45%
Denver, CO
21%
Washington, DC
61%
Atlanta, GA
62%
Miami, FL
50%
Seattle, WA
50%
Boston, MA
83%
New Orleans, LA
50%
San Francisco, CA
50%
$379 Vol.
New York, NY
53%
Los Angeles, CA
24%
Chicago, IL
50%
Houston, TX
50%
Dallas, TX
41%
Phoenix, AZ
2%
Philadelphia, PA
45%
Denver, CO
21%
Washington, DC
61%
Atlanta, GA
62%
Miami, FL
50%
Seattle, WA
50%
Boston, MA
83%
New Orleans, LA
50%
San Francisco, CA
50%
Measurable precipitation means 0.01 inches or more as reported by the PRECIPITATION (IN) figure in the NWS Daily Climate Report (CLI) for the city's station.
A report of trace ("T") does not qualify.
The PRECIPITATION (IN) figure measures total liquid-equivalent precipitation and does not distinguish between precipitation types.
The observation period is the NWS climate day for KNYC: midnight to midnight local standard time. The final CLI report for a climate day is issued the following morning.
This market will resolve according to the NWS Daily Climate Report as published by 2:00 PM ET on the day following the observation date. If multiple versions of the report are issued, the last version published before that time governs. If no figure has been published by that time, this market will resolve to "No".
The resolution source for this market is the NWS Daily Climate Report (CLI) for KNYC, published at https://forecast.weather.gov/product.php?site=NWS&product=CLI&issuedby=NYC.
Market Opened: Sep 20, 2026, 7:09 AM ET
Resolver
0x65070BE91...Measurable precipitation means 0.01 inches or more as reported by the PRECIPITATION (IN) figure in the NWS Daily Climate Report (CLI) for the city's station.
A report of trace ("T") does not qualify.
The PRECIPITATION (IN) figure measures total liquid-equivalent precipitation and does not distinguish between precipitation types.
The observation period is the NWS climate day for KNYC: midnight to midnight local standard time. The final CLI report for a climate day is issued the following morning.
This market will resolve according to the NWS Daily Climate Report as published by 2:00 PM ET on the day following the observation date. If multiple versions of the report are issued, the last version published before that time governs. If no figure has been published by that time, this market will resolve to "No".
The resolution source for this market is the NWS Daily Climate Report (CLI) for KNYC, published at https://forecast.weather.gov/product.php?site=NWS&product=CLI&issuedby=NYC.
Resolver
0x65070BE91...A slow-moving frontal boundary and associated upper-level trough are driving scattered showers and thunderstorms across the Midwest, Ohio Valley, Mid-Atlantic, and Northeast on September 21, according to National Weather Service and NOAA outlooks. This setup, interacting with a moist, unstable air mass, supports the highest precipitation probabilities in those regions, with 60-90% chances in many areas and localized heavy rain risks, while the South and West see lower odds amid lingering heat or drier patterns. Short-term model consensus favors continued activity through Monday before the front shifts, though steering winds and instability details could adjust totals. Traders should watch updated NWS forecasts and radar trends for resolution thresholds tied to measurable rainfall at specific sites.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated


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