A warm front followed by a cold front is driving the market-implied odds toward measurable precipitation (at least 0.01 inches) across Northeast and Midwest cities on September 20, 2026. National Weather Service and Weather Prediction Center guidance indicate an 80–100% probability of measurable rain at stations including Philadelphia, New York, Boston, and Chicago, supported by southwesterly flow ahead of the boundary and cooler northeast winds behind it. This synoptic pattern aligns with historical frontal passages that produce widespread stratiform and convective rainfall in early fall. Traders are watching updated short-range model runs and NWS daily climate reports for final resolution, as minor timing shifts could affect trace versus measurable totals at individual airports.
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 20?
New York, NY
99%
Los Angeles, CA
2%
Chicago, IL
99%
Houston, TX
1%
Dallas, TX
50%
Phoenix, AZ
1%
Philadelphia, PA
75%
Denver, CO
12%
Washington, DC
63%
Atlanta, GA
15%
Miami, FL
99%
Seattle, WA
50%
Boston, MA
75%
New Orleans, LA
6%
San Francisco, CA
50%
$2,974 Vol.
New York, NY
99%
Los Angeles, CA
2%
Chicago, IL
99%
Houston, TX
1%
Dallas, TX
50%
Phoenix, AZ
1%
Philadelphia, PA
75%
Denver, CO
12%
Washington, DC
63%
Atlanta, GA
15%
Miami, FL
99%
Seattle, WA
50%
Boston, MA
75%
New Orleans, LA
6%
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 19, 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 warm front followed by a cold front is driving the market-implied odds toward measurable precipitation (at least 0.01 inches) across Northeast and Midwest cities on September 20, 2026. National Weather Service and Weather Prediction Center guidance indicate an 80–100% probability of measurable rain at stations including Philadelphia, New York, Boston, and Chicago, supported by southwesterly flow ahead of the boundary and cooler northeast winds behind it. This synoptic pattern aligns with historical frontal passages that produce widespread stratiform and convective rainfall in early fall. Traders are watching updated short-range model runs and NWS daily climate reports for final resolution, as minor timing shifts could affect trace versus measurable totals at individual airports.
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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