Highest temperature in Seoul on July 23?

Platform comparison

Market context

Seoul’s highest temperature on 23 July will be set by the Incheon International Airport Station reading published on Wunderground, with settlement depending on the single day’s peak Celsius value rather than any intraday average. At 6am UTC on the settlement day, the market is effectively trading the probability that the day’s maximum ends up in a given range, with USDC paid out according to the contract’s resolution band.

For context, Seoul in July usually sits around the high 20s Celsius, with average highs near 27–28°C and humidity often high enough to make afternoons feel warmer than the thermometer suggests.[1][2] That means the current 0% YES pricing is best read as a statement about where the crowd thinks the final peak will land versus the payout brackets, not a view that Seoul cannot reach a normal summer high. In weather markets, late-morning heating, cloud cover, and any showers can matter more than the headline seasonal average.

The main catalysts are the day’s local forecast path and whether conditions at Incheon stay clear long enough for a brief spike near early afternoon, when urban and coastal temperatures can diverge from morning readings. Traders watching the crypto side will mostly see indirect effects: if broader BTC or ETH risk sentiment shifts hard, it can change speculative flow into short-dated prediction markets, but the settlement itself remains anchored to the Wunderground station print rather than exchange volatility.

Sources: 1 · 2

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

FAQ

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

Can I use Bitcoin directly?

No, Polymarket operates exclusively in USDC on Polygon. You can bridge BTC to USDC via an exchange or bridge service and deposit on Polygon — typically 10-30 minutes processing time.

How volatile are crypto prediction markets?

Crypto markets react to spot prices — a 5% BTC move typically shifts a "BTC above X by date" market 10-20%. Polymarket crypto market liquidity is usually six-figure USD, sufficient for active trading.