Highest temperature in Seoul on July 4?

Platform comparison

Market context

Seoul’s early July heat is a genuine wildcard, with historical highs clustering between 27°C and 31°C, yet the market currently assigns a 0% implied probability to the 29°C bracket hitting on 4 July 2026. This contrarian stance ignores the fact that 29°C sits at the centre of the 117-year record range, where recent data shows Seoul reached 37.7°C in 2025—the highest early July temperature since 1908. The consensus is heavily skewed toward NO, treating 29°C as a minority call despite six other brackets sharing the remaining probability, creating a fragmented field where no single outcome commands majority support.

The value spot lies in the NO side at $0.70, which is the market-f favoured position, yet the 29°C bracket trades at $0.31, implying a one-in-three chance that the high lands exactly there. Traders should monitor the Korea Meteorological Administration’s updated forecast before the noon KST resolution, as thin volume below $1M means prices can move sharply on any new data. Recent records from 2025 show South Korea endured its second-hottest July since 1973, with 22 tropical nights where temperatures did not dip below 29.3°C overnight, suggesting the night-time heat could push the daily high into the 29°C bracket despite the current 0% crowd-implied probability.

The underdog is the 29°C outcome, which leads the fragmented field at 30.5% but is dismissed by the crowd as unlikely. This contrarian angle is supported by the fact that early July highs are genuinely wide, and the 29°C bracket leads only because it sits at the centre of the historical range. With the settlement window ending 2026-07-04T12:00:00Z, the real-world event is the daily high at Incheon Intl Airport Station, and the catalyst is the KMA forecast update, which could shift the probability if the tropical night trend continues into 2026. The market question is whether Seoul’s July 4 high will register exactly 29°C, and the current 0% implied probability for YES is a clear mispricing given the historical data.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seoul on July 4? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 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.