TOTAL VOLUME:
$114.6b
24H VOL:
$136,531,341
24H TRANSACTIONS:
1,380,975,298
OPEN INTEREST:
$1,197,913,311
339,027
Markets across
34,284
events
MATCHED EVENTS:
4,693
PLATFORM COVERAGE:
5
Polymarket:
42%
VS.
Kalshi:
58%
Below 4.8 million sq km
- Kalshi
Below 4.8 million sq km - Kalshi
1W
News
Positive
Negative
Neutral
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Vol.
·
Resolves Oct 2, 2026
Latest in Climate and Weather
Will the extent of the Arctic sea ice be below 4.8 million square km between December 19, 2025 and October 01, 2026?
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Description
This event group tracks the minimum Arctic sea ice extent during the summer of 2026, comparing various threshold ranges to determine market outcomes.
PredictionHero - Resolution Divergence Alerts (RDA)
Divergence Detected
Issue: Time window and threshold precision differences between platformsHero tip: Focus on Polymarket for precise threshold trading; Kalshi markets may resolve earlier due to broader time window. Watch NSIDC updates after December 2025Critical divergence points:
- Polymarket: Uses August 1, 2026 to October 1, 2026 window with measurements to thousandths of a million sq km precision
- Kalshi: Uses December 19, 2025 to October 1, 2026 window with whole number thresholds (e.g., below 4.8m)
Polymarket
This market will resolve according to the minimum Arctic sea ice extent for all days between August 1, 2026 and October 1, 2026, as published by the National Snow and Ice Data Center. This market will remain open until data has been published for October 1, 2026, at which point it will resolve immediately. Any revisions to sea ice extent recorded after data is published for October 1, 2026 will not be considered. The resolution source for this market measures temperatures to thousands of square kilometers (e.g. 4.255 million sq km). Thus, this is the level of precision that will be used when resolving the market. The resolution source for this market will be information from the National Snow and Ice Data Center, specifically the minimum value recorded for any day between August 1, 2026 and October 1, 2026 in the “NH-Daily-Extent” tab of the “Sea Ice Index Daily Extent” data set, available at https://nsidc.org/sea-ice-today/sea-ice-tools. If this resolution source becomes unavailable, another resolution source will be chosen.
Kalshi
The event evaluates multiple thresholds for Arctic sea ice extent during the period from December 19, 2025, to October 1, 2026. Each threshold represents a specific level below which the sea ice extent must fall on at least one day for the corresponding market to resolve as Yes. The primary measurement source is the National Snow & Ice Data Center's (NSIDC) Sea Ice Index Version 4, specifically the Northern Hemisphere daily CSV data. The underlying data point for all markets is the lowest individual daily extent value recorded within the specified timeframe, measured in millions of square kilometers. The markets are structured around progressively lower thresholds, starting from 4.8 million square kilometers and descending to 3.6 million square kilometers. If the daily extent falls below any of these thresholds on a single day within the window, the associated market resolves positively. All markets share the same measurement period and data source, ensuring consistency across the various threshold evaluations. The outcome for each market is binary—Yes if the threshold is breached on any day, No otherwise—allowing participants to assess the likelihood of increasingly severe reductions in Arctic sea ice coverage.