Highest temperature in Seoul on June 27?

Platform comparison

Active sub-markets

Market context

On 27 June 2026, Seoul will experience its early-summer peak heat, with temperatures expected to climb into the high 20s Celsius before the monsoon rains intensify. The market tracks the highest temperature recorded at Incheon International Airport, a coastal site that typically registers slightly cooler readings than the city centre due to sea influence. Current crowd-implied probability of 0% for any specific high range suggests traders are either uncertain about the exact threshold or believe the settlement will fall outside the offered brackets, a divergence often seen when platforms like Polymarket use decimal odds while Kalshi relies on implied probability with stricter KYC requirements.

Historical data frames this probability: June in Seoul averages 19–28°C, with the warmest day in 2026 so far reaching 34.0°C on 19 June, while the average warmest day in June is 28.06°C with a high of 26.7°C[6][7]. Incheon’s coastal location usually caps highs around 26–27°C, making a 34°C event unlikely unless an extreme heatwave coincides with the monsoon onset. Platforms diverge here: Betfair’s decimal odds may reflect this nuance more granularly than Smarkets’ flat fee structure, which can compress probability ranges for low-liquidity events.

Traders should monitor the Korea Meteorological Administration’s short-range forecasts for monsoon timing, as late-June rain could suppress temperatures below 25°C[4]. Recent news notes South Korea’s spring was the second-hottest ever, with May the hottest on record, driven by elevated sea surface temperatures[10]. This heat legacy may push June highs toward 28–30°C, but the monsoon’s arrival—typically late June to mid-July—remains the critical dependency[1][2]. Watch for official announcements on heatwave alerts, as these often precede temperature spikes. Fee structures and KYC reach vary: Polymarket’s low fees attract retail traders, while Kalshi’s institutional focus may limit liquidity for niche weather markets.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Seoul on June 27? 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.

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.

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.