Highest temperature in Seoul on July 31?

Platform comparison

Market context

Seoul’s summer heat is being measured at Incheon Intl Airport Station for settlement purposes, so the key variable is the day’s *highest* station reading rather than the city’s typical daytime feel. In practical terms, a programmer tracking this market would watch the Wunderground daily history page for RKSI and poll it after the settlement window closes, because the result depends on the maximum Celsius value logged for 31 July, not on a forecast headline or a single noon observation.[9]

The 0% YES print should be read against a backdrop of repeated July heat extremes in the capital area. Seoul has posted record or near-record summer heat before, including 38.3C on 31 July 2018 and 22 consecutive tropical nights in July 2025, while the city’s long-run July average maximum is far lower, around 29C, which shows how sharply outcomes can diverge on a heatwave day.[2][1][15] For a trading workflow, that means conditional orders tied to a threshold band are more useful than binary assumptions about “hot” weather; the actionable question is whether the station’s daytime peak gets into the upper 30s or remains closer to the high-20s norm.[15][16]

The main catalysts are the local heatwave pattern, the timing of any KMA warnings, and whether nearby observing stations are already printing extreme highs, since those signals often precede a late-afternoon peak. Reuters reported that South Korea had just set a nationwide modern-era temperature record of 41.4C in Yangsan on 31 July 2026, indicating a strongly elevated thermal backdrop even though that reading was well south-east of Seoul.[7] For a rules-driven approach, the useful checks are the intraday Wunderground updates, KMA bulletins, and any schedule changes that might alter airport observations; if the heat ridge holds through the afternoon, the upside tail on the station maximum widens materially.[6][7]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Review UK, which mirrors the Polymarket order book directly.

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 Polymarket Review UK. 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.

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 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.