SimpleFunctions
Winner-take-all · 5 outcomes5 contractsPolymarketrefreshed 2 min agoCloses Oct 1, 2026 · 145d

Min Arctic sea ice extent this summer?

Bracket4.2-4.4m sq km

Leader sits at 47% across 5 bound outcomes, runner-up at 14%. This is a winner-take-all market — the headline is the leader’s price, not an arithmetic mean.

Leader probability

47%

<4m sq km

runner-up 14¢leader 47¢

Outcomes

5

winner-take-all

Runner-up

14¢

4.0-4.2m sq km

Spread

33pp

contested

24h volume

$93

thin orderbook

Closes

Oct 1, 2026

145 days

Venue

Polymarket

5 bound

30-day trend

0%50%100%-30d-3w-2w-1wtoday<4m sq km: 58% (28 days, 22 points)<4m sq km: 58% on 2026-05-084.0-4.2m sq km: 15% (28 days, 22 points)4.0-4.2m sq km: 15% on 2026-05-084.2-4.4m sq km: 10% (28 days, 27 points)4.2-4.4m sq km: 10% on 2026-05-07
<4m sq km58¢4.0-4.2m sq km15¢4.2-4.4m sq km10¢
Top 3 candidates by current price · 28d

Bracket family

How the bracket ladder is priced.

Each row is one outcome on the venue. Sorted by 24h volume — the heaviest book is at the top.

Analysis

This contract predicts that the Arctic's minimum sea ice extent this summer will fall between 4.2 and 4.4 million square kilometers. Currently priced at 44% on Polymarket, this outcome sits between the 4.0–4.2m range (33%) and represents the modal expectation among traders. Arctic sea ice extent depends primarily on spring and early-summer air temperatures, ocean warmth, and atmospheric circulation patterns. The key catalyst is the seasonal minimum measurement, typically recorded in mid-September, which depends on conditions from now through late summer. Factors driving the current pricing include recent ice-tracking data through May, seasonal climate forecasts from NOAA and other agencies, and historical trends showing multi-year oscillations in minimum extent. The contract will resolve based on satellite observations from the National Snow and Ice Data Center (NSIDC) or equivalent authoritative source.

  • Current Arctic sea ice extent as of early May 2026 relative to recent 5–10-year average and historical trends
  • Spring and early-summer air temperatures in the Arctic and adjacent regions, measurable via reanalysis data and weather forecasts
  • Sea surface temperatures in ice-marginal zones, which influence melt rates from June through August
  • Arctic Oscillation and other large-scale atmospheric circulation modes that affect wind patterns and ice transport
  • NOAA seasonal climate outlook and model ensemble forecasts for northern-hemisphere summer conditions

What moved the line

  • May 64.0-4.2m sq km16pp3317¢ · Polymarket
  • May 6<4m sq km12pp3850¢ · Polymarket
  • May 74.6-4.8m sq km8pp157¢ · Polymarket
  • May 64.6-4.8m sq km7pp815¢ · Polymarket
  • May 24.0-4.2m sq km6pp2329¢ · Polymarket

Recently closed in general

These markets stopped trading. Last odds and any captured outcome are shown above — full settlement detail lives at the venue.

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How we compute these odds

SimpleFunctions aggregates live prediction-market contracts from Kalshi and Polymarket. Each slug groups contracts that resolve on the same underlying event, identified by venue event_id.

For binary slugs, the headline probability is the liquidity-weighted mid-price across all bound contracts. For multi-outcome slugs (e.g. elections with 3+ candidates), the headline is the leader’s price; we never arithmetically average disjoint outcomes — that would produce a number with no real-world meaning.

Snapshots refresh every 5 minutes during market hours; daily aggregates are computed at 04:00 UTC. The 30-day sparkline is drawn from per-ticker daily means stored in market_indicator_daily; 24h delta and movement events are derived from the same source.

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