Highest temperature in Beijing on June 30?

Platform comparison

Market context

The underlying event is the peak daytime heat recorded at Beijing Capital International Airport on 30 June 2026, measured in degrees Celsius and resolved via Wunderground data. A power-user evaluating this market programmatically would first note the current crowd-implied probability of 0% for any outcome, suggesting the market currently expects no valid resolution or a data anomaly, which is highly unusual for a standard weather event in early summer.

Historical patterns frame this probability sharply: June in Beijing consistently delivers daytime averages of 30°C, with daily highs frequently reaching 32°C, as seen in recent Polymarket resolutions for 12 and 25 June 2026 where 32°C was the frontrunner at 100% certainty [1][2]. Even during record-breaking heatwaves, such as the recent event where Beijing hit 106°F (41°C), valid temperature data was recorded and resolved [9]. The 0% probability therefore likely reflects a technical glitch in the market setup rather than a meteorological expectation of zero heat, given that June is one of Beijing’s hottest months with highs ranging from 82°F to 93°F [4].

Traders should monitor Wunderground’s data feed directly for the 30 June entry, as the settlement depends entirely on this specific source updating correctly. Recent news confirms Beijing is currently experiencing scorching heatwaves that shattered June temperature records, indicating that valid high-temperature data will almost certainly exist [9]. The primary catalyst is the automated data ingestion from Wunderground; if the feed fails to populate for 30 June, the market may resolve as void, but given the active heatwave and historical consistency, a data gap is improbable. Programmatic approaches should include conditional orders that trigger only upon Wunderground confirming a valid temperature reading for the target date.

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

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.

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.