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Min Arctic sea ice extent this summer?
Climate and Weather
polymarket
kalshi

Min Arctic sea ice extent this summer?

Total volume:
$75,005
Volume 24h:
$279
47%
Liquidity:
$4,163
6%
Open interest:
$5,195
3%

Below 4.8 million sq km

 - Kalshi

Below 4.8 million sq km - Kalshi

98%

+1%

1W

News

Positive

Negative

Neutral

Hover marker for details

Aug 20

Aug 21

Aug 22

Aug 23

Aug 24

Aug 26

Aug 27

Vol.

$185.9

·

Resolves Oct 2, 2026

Will the extent of the Arctic sea ice be below 4.8 million square km between December 19, 2025 and October 01, 2026?

92%chance
Amount

$

Trade on
kalshi

Trade on Kalshi

Join Kalshi and score $25 for your first trade.At 98¢ buys you 102 shares | Odds: 92% Total Payout: $102 | Net Profit: $2 Multiplier: 1.02x | ROI: 2% | APY: 23% 36 days to resolution
You will be redirected to the platform to complete this trade.
Outcome
Trade
Chance %
Price
Spread
Liquidity
Volume
24h
7d
Open Interest
Ends in
Result
MUI X License key version mismatch
Total markets: 16

Description

This event group concerns the minimum Arctic sea ice extent recorded during the summer of 2026. Markets across Polymarket and Kalshi will resolve based on data from the National Snow and Ice Data Center, but with differing timeframes and threshold definitions.

PredictionHero - Resolution Divergence Alerts (RDA)

Divergence Detected

Issue: Divergence in observation window and threshold definitionsHero tip: Focus trades on Polymarket for summer-specific bets; Kalshi markets may resolve earlier due to broader winter inclusion

Critical divergence points:

  • Polymarket: Resolves based on minimum extent recorded between August 1, 2026 and October 1, 2026 using NSIDC's NH-Daily-Extent data
  • Kalshi: Resolves if any day between December 19, 2025 and October 1, 2026 records extent below specified thresholds
Our PredictionHero Resolution Divergence Alerts (RDA) are there to help users identify potential differences across platforms. They do not replace or supersede the official rules and description of any prediction market. Users are solely responsible for reviewing and understanding the applicable rules and resolution criteria before placing any trade or bet. If you notice a potential inconsistency, discrepancy, or error in an alert, please report it to our team so we can review and improve the accuracy of our data.
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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 recorded extent on any day within the period falls below any of these thresholds, the respective market resolves to Yes. The secondary rule consistently defines the underlying data source and calculation method across all markets, ensuring uniformity in how the extent values are determined and reported.

Frequently asked questions

The dashboard for the Arctic sea ice extent market aggregates data from multiple venues, showing how traders price the probability of different ice extent outcomes this summer. It displays current odds, volume of $72,457, and 24-hour volume of $410 across platforms, offering a consensus view of market expectations for this environmental indicator.

On Polymarket, this market is priced through trader sentiment and current data trends. Analyst forecasts for the Arctic sea ice extent market often incorporate long-term climate models and historical patterns, which can differ from short-term market pricing. While prediction markets reflect real-time betting activity and may shift rapidly with new data, analyst reports usually provide broader context and deeper scientific insights. The gap between these two can vary widely, especially as new observations emerge. Understanding both perspectives helps gauge uncertainty and potential market movements.

On Polymarket and Kalshi, prices can vary because of differences in user bases, liquidity, and market design. Polymarket and Kalshi can show different implied probabilities for the same outcome because of liquidity, fee structure, participant mix, and how each venue defines the contract. For instance, Polymarket currently favors Will the minimum Arctic sea ice extent this summer be between 4.4m & 4.6m square kilometers? at 34.2%, while Kalshi leans toward Will the extent of the Arctic sea ice be below 4.8 million square km between December 19, 2025 and October 01, 2026? at 92.0%. Such spreads of 57.8 percentage points are normal in markets with differing participation and risk profiles.

This market resolves around Oct 2, 2026, with the outcome confirmed once the event is verifiable from credible public reporting. The final determination will hinge on authoritative measurements of Arctic sea ice extent from trusted scientific sources, ensuring an objective and transparent close.

Several key signals could influence this market before Oct 2, 2026. Satellite updates showing unexpected melt or freeze rates will shift expectations quickly. Reports from polar research institutions, especially those indicating abrupt changes in ice thickness or area, often trigger sharp market moves. Weather anomalies such as prolonged storms or unusual solar activity can also impact outcomes. Additionally, large-scale climate policy announcements or international agreements may affect long-term trends and trader sentiment, potentially moving prices in either direction as the resolution date approaches.