Highest temperature in Shanghai on July 4?

Platform comparison

Market context

The underlying event is the peak daily temperature recorded at Shanghai Pudong International Airport on 4 July 2026, measured in degrees Celsius and sourced from Wunderground. Historically, July in Shanghai is a period of intense heat, with average daily highs climbing from 84°F to 88°F (roughly 29°C to 31°C) and frequent days exceeding 35°C (95°F) during sunny spells [1][8]. The current crowd-implied probability of 0% for a specific high-temperature range appears counter-intuitive given these baselines, suggesting the market may be betting on a narrow, cooler band or that the specific range in question is statistically improbable for this date. A power-user evaluating this tooling would programmatically ingest historical Wunderground data for ZSPD to calculate the probability distribution of peak temperatures, likely finding that temperatures above 30°C are the norm, making a 0% probability for a high range a signal to scrutinise the range definition rather than the weather itself.

Traders must monitor the immediate forecast for scattered thunderstorms and high humidity, which are the primary catalysts for temperature suppression on this day. Current forecasts indicate a 53% chance of scattered thunderstorms with a peak temperature of 79°F (26°C) to 99°F (37°C), heavily dependent on cloud cover and rain intensity [3][4]. The risk of thunderstorms is the critical dependency; a heavy downpour in the afternoon would cap the maximum temperature well below the seasonal average, whereas clear skies would push it toward the 35°C ceiling. A recent forecast from The Weather Network highlights the "hot and humid" conditions with a moderate risk of afternoon thunderstorms, which directly impacts the resolution source [3]. Programmatically, a conditional order would trigger on real-time Wunderground updates showing a drop in solar radiation or a spike in precipitation probability, adjusting the position as the storm risk materialises.

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 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 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.