Highest temperature in Seoul on May 23?

Platform comparison

Active sub-markets

Market context

On 23 May 2026, Seoul's highest temperature will be recorded at Incheon International Airport Station and assigned to one of several temperature bands. The settlement hinges on Weather Underground's historical data feed for that specific date, making data availability and measurement consistency critical factors. Across major prediction platforms, this market reveals divergent approaches to weather resolution: Polymarket uses decimal odds and settles against a single external source, whilst Kalshi operates under CFTC oversight with stricter position limits on weather derivatives, and Betfair's lay-betting mechanics allow traders to short temperature ranges directly. Fee structures vary materially—Polymarket charges 2% on winnings, Kalshi typically 1–2% depending on contract type, and Smarkets takes 2% but offers lower minimum stakes for retail traders in certain jurisdictions.

Historical May temperatures at Incheon show considerable year-to-year variance. Between 2015 and 2024, highs on 23 May ranged from 22°C to 29°C, with a median around 26°C. The 0% crowd probability currently assigned suggests either extreme confidence in a specific outcome or insufficient liquidity to establish a baseline. Late-spring Seoul weather depends heavily on the East Asian monsoon system's onset timing and any tropical systems tracking northward; the Korean Meteorological Administration typically issues seasonal forecasts in April that traders monitor closely.

The settlement window closes at 12:00 UTC on 23 May 2026, allowing only same-day resolution. Traders should verify Weather Underground's historical data access for that date well before settlement, as platform outages or data delays have occasionally prolonged resolution on weather markets. Cross-referencing against the Korea Meteorological Administration's official records provides a secondary check, though Weather Underground remains the binding source here.

Methodology

We read Highest temperature in Seoul on May 23? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On PolyGram, 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.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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?

Not under $1,500 of lifetime trading volume. Above that threshold, PolyGram triggers a quick verification flow that finishes in 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.