Highest temperature in Seoul on July 4?

Platform comparison

Market context

The underlying real-world event is the highest temperature recorded at Incheon International Airport on 4 July 2026, measured in degrees Celsius. Polymarket prices the contract for a 29°C hit at $0.31 YES, implying a 30.5% chance, while the NO side trades at $0.70, reflecting the market’s view that any other temperature bracket is more likely. This conditional token sits on Polygon and settles in USDC, with the settlement window closing at noon KST on 4 July 2026.

Historical July data frames this low probability: Seoul’s average July maximum is 27.7°C, with daily highs typically reaching 30°C but often tempered by monsoon rain [2][3]. The 29°C bracket is the single most likely outcome yet remains a minority call, as six other temperature ranges share the remaining probability [1]. Recent record-breaking heat in July 2025, when South Korea hit 41.2°C and experienced 22 tropical nights, shows volatility is possible, but such extremes are outliers rather than norms [9].

Traders should monitor the Korea Meteorological Administration’s short-range forecasts for shower intensity and precipitation probability, which currently indicate 60% chance of slight rainfall [6]. The monsoon season (Jangma), active from late June to mid-July, often brings concentrated heavy rain in July, suppressing peak temperatures [2]. Any sudden shift in cloud cover or rain timing could alter the day’s maximum, making real-time weather updates the key catalyst for this on-chain position.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Seoul on July 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

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.

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.