Highest temperature in Seoul on May 28?

Platform comparison

Active sub-markets

Market context

The settlement hinges on the maximum temperature recorded at Incheon International Airport on 28 May 2026, with the crowd currently assigning zero probability to any outcome. Seoul's late May climate typically sits in the warm-to-hot range, with historical highs around 28–32°C at this station during the period. The 0% implied probability suggests either a technical issue with market setup or genuine uncertainty about which temperature band will ultimately contain the day's peak reading.

Historical May data from Incheon shows considerable year-to-year variation. The station has recorded highs ranging from 21°C to 34°C in late May across recent decades, reflecting Seoul's transition into early summer. A wet season system moving through the Korean peninsula in late May can suppress temperatures significantly, whilst clear, high-pressure systems drive them upward. The absence of any meaningful probability mass across the available ranges indicates traders have not yet calibrated expectations against seasonal norms or specific weather patterns forecast for that week.

The key variable is the large-scale atmospheric setup in the final week of May 2026. Tropical cyclone activity in the western Pacific, the position of the North Pacific high-pressure system, and moisture transport from the South China Sea will all influence whether Seoul experiences typical spring warmth or an anomalous cool spell. Weather model consensus typically becomes reliable only 10–14 days ahead; traders should monitor extended forecasts from the Korea Meteorological Administration and international centres as May progresses to identify whether conditions favour the cooler or warmer end of the historical distribution.

Methodology

We track Highest temperature in Seoul on May 28? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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?

On Who Will Win, which mirrors the Polymarket order book at 0% fees. 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 does it cost to trade on Who Will Win?

Zero. Who Will Win routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.

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.