Highest temperature in Seoul (Incheon) on August 4?

Platform comparison

Market context

The contract is about the **highest temperature at Incheon International Airport Station** on 4 August, and the live market is pricing a broad range of summer heat rather than an extreme spike. Polymarket’s contract page shows the crowd clustered around **29°C to 32°C**, with **29°C** the current leading outcome at **37%** and **30°C/31°C/32°C** each at **19%**; by contrast, the prompt says the current crowd-implied probability for **YES** is **0%**, which suggests no separate yes/no overlay is being priced here and the actionable signal is the temperature band distribution itself.[8]

Recent South Korean weather coverage frames the day as hot but not exceptional for the season. The Korea Meteorological Administration has forecast **Incheon at 37°C** and **Seoul at 38°C** for the 4th, with nationwide highs of **30°C to 38°C** and morning lows of **23°C to 27°C**.[2][3] That sits above August norms: WeatherSpark puts Seoul’s typical range around **75°F to 85°F** on 4 August, while an August guide for Incheon lists an average maximum near **29°C**.[5][10] For traders, the key comparison is whether the airport station runs several degrees cooler than inland Seoul, or whether the current heatwave and strong afternoon heating push the observed peak into the mid-30s. Reuters reported Korea’s record heatwave was still intensifying on 31 July, with the national record lifted to **41.4°C** in Yangsan, so latest KMA updates and local cloud/rain timing remain the main catalysts to watch.[9]

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

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi vs Polymarket 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.