Highest temperature in Seoul on June 30?

Platform comparison

Market context

Seoul is bracing for a sharp heat spike as the monsoon front stalls, pushing daytime highs toward 30°C with overnight lows lingering near 19°C, a pattern that has already driven the crowd-implied probability of a record-breaking June 30 temperature to zero[1]. This near-certain “no” reflects the market’s recognition that Incheon International Airport, the designated resolution site, typically records temperatures 1–2°C lower than central Seoul due to its coastal exposure and sea breeze, making an extreme outlier on the final day of June statistically improbable under current conditions[4].

Historically, late June in Seoul sees temperatures peak between days 21–30, with average highs of 21.8°C, but extreme spikes above 30°C are rare and usually confined to inland areas like Gwangju, which recently hit 30°C while Seoul stayed at 27°C[1][8]. The 0% probability aligns with this pattern: Incheon’s maritime buffer has consistently prevented it from matching Seoul’s inland heat surges, even during the 2026 early summer heatwave that saw Seoul reach 27°C and Gwangju 30°C[1].

Traders should monitor the Korea Meteorological Administration’s short-range forecasts for any sudden shifts in the monsoon front, as a northward surge could trap heat over Incheon and invalidate the current consensus[5]. Additionally, watch for real-time updates from Wunderground on the morning of June 30, as a sudden drop in wind speed or an unexpected cloud cover break could trigger a rapid temperature spike, though such events remain low-probability given the prevailing humid, cloudy conditions[3]. A recent AccuWeather forecast confirms June 2026 highs will range 29–33°C (85–91°F), but Incheon’s coastal location typically keeps it below this range[2].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Seoul on June 30? 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 Prediction Today, which mirrors the Polymarket order book at 0% fees.

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Prediction Today trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.