Highest temperature in Seoul on July 3?

Platform comparison

Market context

Seoul is currently experiencing its most intense July nighttime heat wave in over a century, with temperatures failing to drop below 29.3°C between Wednesday night and Thursday morning. This unprecedented tropical night streak has pushed the city to 22 such nights this month, shattering the previous record of 21 set in 1994[1]. For a power-user evaluating prediction market tooling programmatically, this real-world anomaly frames the current 0% crowd-implied probability for a specific high-temperature range as a statistical outlier rather than a baseline expectation. Historical averages for July in Seoul typically see highs between 81°F and 85°F (27.2°C to 29.4°C), rarely exceeding 91°F (32.8°C)[2], yet the recent surge to 37.7°C marks the highest early July temperature in 117 years of records[5].

Traders approaching this market via conditional orders or copy-trading bots must monitor the Korea Meteorological Administration’s daily tropical night updates and any sudden shifts in monsoon patterns that could disrupt the current heat dome. The primary catalyst remains the persistence of this record-breaking heat, which has already driven Seoul to its second-hottest July since 1973 with an average of 27.1°C[6]. A recent report from the Korea Herald confirms the city has set a new record for the highest number of tropical nights in July since modern observations began over a century ago[1]. Programmatically, one would script alerts for Wunderground data feeds at the Incheon Intl Airport Station to capture real-time deviations from the 37.7°C peak, as any further escalation would invalidate the current 0% probability stance for lower ranges. The settlement window closing on 3 July 2026 requires precise timing to align bot execution with the final data release.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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 Polymarket Bot UK. 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 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 Polymarket Bot UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.