Highest temperature in Seoul on July 27?

Platform comparison

Market context

Incheon International Airport’s hottest reading on 27 July is the key settlement point, and the current crowd-implied probability puts **31°C** as the favourite at **37%**, with **30°C** close behind at **32%**. That leaves the market still centred on the low 30s, even though the user-facing title says Seoul; the resolution source is the airport station, so traders should weight the airport microclimate and not central Seoul headlines.

Historically, late July in South Korea is a hot, humid period, but it is also the heart of the monsoon window, which can cap the day’s high through cloud cover and rain. Seasonal guides describe July as wet and muggy, with average highs around 30°C and frequent heavy rainfall, while recent South Korean reporting has also pointed to periods of extreme heat and limited rainfall later in the summer. That combination explains why the consensus sits around 30–32°C rather than much higher, and why the underdog cases are split between a modest heat squeeze and a rain-muted day.

For traders, the main catalysts are the local forecast for Incheon, the timing of any afternoon showers, and whether cloud cover lingers into peak heating hours. Because the market resolves on the highest temperature recorded during the day, a brief clear spell can still push the outcome up a notch, while an earlier rain band can lock in the lower bins. With the crowd already pricing 30–31°C as the core band, the value question is whether the market is underestimating a hotter-than-normal break from the monsoon pattern or overestimating the chance of full sunshine.

Sources: 1 · 2 · 3 · 4 · 5

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Who Will Win. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.