Highest temperature in Shanghai on July 3?

Platform comparison

Market context

The real-world event this market tracks is the peak daytime temperature recorded at Shanghai Pudong International Airport on 3 July 2026, measured in degrees Celsius. Current crowd-implied probability sits at 0% for any specific outcome, yet trading data reveals the frontrunner is 31°C at 42%, with 30°C holding 32%, suggesting the market is actively pricing a narrow band despite the headline probability confusion[2].

Historical patterns for early July at this station show daily highs typically rising from 84°F to 88°F (29°C to 31°C), rarely dipping below 75°F (24°C) or exceeding 95°F (35°C)[1]. Climate data specifically notes that 3 July is often the coldest day in the first ten days of July, with a recorded average of 24.3°C (75.7°F), contrasting sharply with the warmest day later in the month reaching 32.5°C (90.5°F)[8]. This variability frames the current 0% probability as a likely data anomaly rather than a genuine expectation of no resolution, given that temperatures consistently fall within measurable ranges.

A programmatic trader should monitor the persistent subtropical monsoon flow and high humidity above 75%, which currently limit radiative cooling and keep overnight lows in the 24–26°C range[3]. Key catalysts include thundery showers forecast for the day, which can suppress peak temperatures, and the gradual increase in shortwave solar energy rising from 5.1 kWh to 5.6 kWh over the month, potentially driving higher highs if cloud cover clears[1]. Recent BBC Weather reports confirm light rain and thundery showers are active, with a high of 29°C (85°F) already recorded, providing immediate context for algorithmic models adjusting to real-time conditions[5].

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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

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 Polymarket Review 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.