Highest temperature in Seoul on July 9?

Platform comparison

Market context

Seoul is experiencing record-breaking heat in early July 2026, with temperatures reaching 37.8°C on 8 July, the highest ever recorded for this period in 117 years of data [7][9]. This extreme warmth frames the current Polymarket contract, where the crowd-implied probability for a 26°C threshold sits at 0% YES, reflecting traders’ certainty that temperatures will far exceed this modest level. The market resolves based on the highest temperature at Incheon International Airport, sourced from Wunderground, and settles on 9 July 2026 at 12:00 UTC, with USDC payouts on the Polygon network via conditional tokens.

Historically, Seoul’s July highs average between 81°F and 85°F (27.2°C–29.4°C), rarely dropping below 74°F (23.3°C) or exceeding 91°F (32.8°C) [1]. However, 2025 saw South Korea’s second-hottest July since 1973, averaging 27.1°C, and 2026 has already surpassed prior early-July records [4][7]. The 0% probability for 26°C is consistent with this trend, as even average conditions exceed this threshold, and recent extremes have pushed temperatures nearly 12°C higher.

Traders should monitor daily weather bulletins from the Korea Meteorological Administration and Wunderground updates for Incheon, as cloud cover, monsoon progression, or heatwave extensions could shift the final reading [4]. A recent report from Anadolu Ajansı confirms Seoul’s 37.7°C peak on 8 July, reinforcing the likelihood of sustained high temperatures through settlement [9]. With no bullet points or moralising, the on-chain mechanics remain clear: USDC stakes on Polygon determine payouts once the Wunderground data confirms the day’s peak temperature.

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 PolyGram. 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'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 PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.