Highest temperature in Shanghai on July 27?

Platform comparison

Market context

Shanghai is in a classic midsummer setup: hot, humid and prone to passing showers, with July average highs around **32°C** and roughly **135 mm** of rain across the month. That makes the market’s **0% yes** price look like the favourite backing the low side, but it also leaves room for a contrarian view if the day turns into a clear, sun-drenched one with reduced maritime moderation. [2]

Historically, Shanghai’s July temperatures tend to cluster around the low 30s rather than extreme heat, which is why a very high maximum is a genuine underdog outcome rather than a routine one. The key handicapper’s read is that the consensus is effectively “warm, but not exceptional”; value on the upside would sit in a sharp heat spike above the usual range, while the favourite remains any outcome that settles in the broad 30s. [2]

For traders, the main catalysts are straightforward weather drivers rather than scheduled announcements: cloud cover, rainfall timing, and how much the local heat build-up persists through the afternoon at Pudong Airport. The Met Office forecast for Shanghai already flags warm conditions and some rain risk, which can cap extremes if showers arrive early, while a dry, sunny spell would support the over. [1]

Sources: 1 · 2

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

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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'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.

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