Highest temperature in Seoul on July 31?

Platform comparison

Market context

The real-world event is the day’s **highest temperature at Incheon Intl Airport Station**, which the market uses as the settlement reference for the 31 July reading. The contract is currently priced at **0% YES**, so the implied market view is that the outcome is either effectively unavailable to trade or that participants see the specified temperature range as extremely unlikely to be hit once the day is underway.

Historically, late-July Korean heat can still produce sharp intraday spikes. Seoul’s climate record shows a July record high of **38.4°C**, while recent reporting has described Seoul and surrounding areas as running unusually hot, with Seoul logging **22 tropical nights** in July and the capital’s hottest July night on record being **29.3°C** on 30 July unless an even warmer overnight minimum occurred on 31 July.[14][1] Incheon is typically cooler than inland Seoul, but it has still reached **35.2°C** in past hot spells, which is enough to keep upper temperature bands in play if the regional heat dome persists.[2]

For traders, the key catalysts are the day’s local forecast evolution, cloud cover and any sea-breeze moderation around the airport, plus the timing of the afternoon peak before the settlement window closes at **12:00 UTC**. The strongest external risk factor is whether the broader South Korean heatwave continues; recent coverage has noted extreme heat elsewhere in the country, including **41.4°C in Yangsan** on 31 July, and heat-related emergency dispatches were already running high nationwide.[10][17] That supports a live tail-risk on higher temperature bins, even if the market is currently implying near-zero probability.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.