Highest temperature in Seoul on July 1?

Platform comparison

Market context

The underlying event is the peak daily temperature recorded at Incheon International Airport on 1 July 2026, measured in degrees Celsius and sourced from Wunderground. Historical patterns for South Korea in July show a hot, humid monsoon climate where average daily highs approach 30°C, often feeling like over 34°C due to humidity exceeding 80%[3]. While the current crowd-implied probability for a specific outcome sits at 0%, comparable markets on Polymarket for Seoul on 1 July 2026 assign a 58% chance to 30°C, with 29°C as the next likely outcome at 32%[1]. This divergence suggests traders should scrutinise whether the 0% figure reflects a data error or a specific bet against the 30°C range, given that July is the rainiest month yet still delivers intense heat when rain clears[3].

A power-user approaching this programmatically must monitor the Korea Meteorological Administration’s short-range forecasts for precipitation probability and cloud cover, as these directly suppress peak temperatures[5]. The primary catalyst is the timing of the Jangma monsoon season, which typically ends mid-July; if heavy rain persists on 1 July, temperatures will likely fall below 30°C, whereas a clear, sunny day post-rain will push highs toward or above that threshold[3]. Recent records show Seoul hitting 37.7°C in early July, the highest in 117 years, indicating that extreme heat events are possible even during the wet season[10]. Traders should also watch for sudden shifts in humidity and wind direction, as light SW winds can trap heat, while SE winds may bring cooler air from the ocean[5]. Conditional orders should be triggered by real-time Wunderground updates once the monsoon window narrows, ensuring execution aligns with the actual settlement data.

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

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.

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.