Highest temperature in Seoul on July 3?

Platform comparison

Market context

Seoul’s July 3, 2026, high temperature hinges on whether a heat dome pushes readings into the 30–31°C range or a passing monsoon front drags them down to 27–28°C. The market currently assigns 0% probability to the 29°C bracket, implying traders see that specific outcome as virtually impossible given the volatile early-July weather patterns.

Historical data frames this 0% stance: July in South Korea is the rainiest month, with daily average highs nearing 30°C but frequently disrupted by concentrated, heavy rainfall and humidity above 80%[2]. While Seoul recorded a record 37.1°C on July 8, 2008, the typical range remains wide, with six other temperature brackets sharing the remaining probability and no single outcome commanding majority support[1][7]. Programmatic traders would likely filter Wunderground’s RKSI station data for real-time precipitation spikes, as a passing front could instantly invalidate the 29°C hypothesis.

Key catalysts include the monsoon season’s end date, which typically falls in mid-July but can extend late, and the intensity of short, heavy rainfalls that characterise July[2]. Traders must monitor the Korea Meteorological Administration’s short-range forecasts for cloud cover and precipitation probability, as even a 10% chance of rain can shift the high from 30°C to 28°C[4]. Recent warnings from meteorologists suggest this summer could be South Korea’s hottest yet, adding volatility to the temperature range[7]. A conditional order strategy would trigger NO positions if Wunderground reports precipitation exceeding 5mm before noon, reflecting the high likelihood of monsoon interference.

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 Kalshi Fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi Fees 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.