Highest temperature in Seoul on July 1?

Platform comparison

Market context

On 1 July 2026, the highest temperature recorded at Incheon International Airport will determine the outcome of a prediction market where the crowd currently assigns zero probability to any outcome above freezing, despite historical data confirming Seoul’s July highs routinely reach 30°C. This stark divergence between the 0% implied probability and the 58% market share for 30°C on Polymarket highlights a critical mispricing, as short-range models and climatological records consistently place Seoul’s daily highs between 27°C and 30°C during the monsoon season [1][3].

Historical patterns from Weather Spark and AccuWeather show that July in Seoul sees daily highs climbing from 81°F to 85°F (27°C to 29°C), rarely dipping below 74°F (23°C) or exceeding 91°F (33°C), with humidity pushing felt temperatures above 34°C [3][5]. The current 0% probability on the primary market contradicts these established norms and the strong consensus on Polymarket, where traders overwhelmingly favour 30°C, suggesting a potential arbitrage opportunity for those who recognise the meteorological reality over the anomalous crowd sentiment [1][9].

Traders should monitor the Korea Meteorological Administration’s hourly forecasts, updated at 14:00 on 1 July, for real-time temperature spikes, as well as Wunderground’s official resolution data for the Incheon station [8]. Recent reports indicate Korea is already experiencing July-like heat in early June, with temperatures hitting 32°C, a precursor that often signals an intense monsoon period with concentrated rainfall in central inland cities like Seoul [4][7]. The settlement window closes at 12:00 UTC on 1 July 2026, making immediate attention to the 9 AM to noon temperature window essential for accurate positioning [6].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seoul on July 1? 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

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 Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 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.