Highest temperature in Seoul on July 20?

Platform comparison

Market context

Seoul faces its peak summer heat on 20 July 2026, with the Incheon International Airport station expected to record temperatures in the high 20s or low 30s Celsius. The prediction market currently prices the YES outcome at 0%, implying the crowd believes the temperature will not fall into the specific range offered, likely a lower bracket inconsistent with typical mid-July extremes.

Historical July data for Seoul anchors daily highs between 25°C and 30°C, often feeling like 34°C due to humidity exceeding 80% during the Jangma rainy season which lingers until mid-to-late July [1][4]. Comparable cases show that while cooler spells can dip to 18°C after rain, sustained midday heat routinely pushes readings into the low 30s°C, making a 0% probability for a lower range statistically questionable unless the market targets a very high threshold [2].

Traders should monitor the official weather schedule from the Korea Meteorological Administration and real-time updates on Wunderground, the designated resolution source for this contract [1]. The market settles via the UMA Optimistic Oracle on Polygon, triggering an automatic USDC payout once the official daily maximum is logged, with a two-hour dispute window before funds clear [3]. Watch for any sudden shifts in the rainy season’s end date, as a prolonged wet spell could suppress temperatures below the expected 30°C anchor.

Sources: 1 · 2 · 3 · 4

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.