Highest temperature in Toronto on July 15?

Platform comparison

Market context

Toronto Pearson International Airport is set to record its peak temperature for 15 July 2026, with the outcome determined by the highest reading in degrees Celsius at the station before the settlement deadline. The current prediction market shows a 100% implied probability for the “YES” outcome, yet this binary framing obscures the actual distribution of likely temperature ranges. On Polymarket, the frontrunner is 32°C at 38%, followed by 31°C at 29%, indicating the crowd expects a hot day but remains divided on the precise peak [1].

Historical mid-July highs at Toronto Pearson typically cluster between 28°C and 34°C, with 32°C representing a strong but not extreme summer peak. Current real-time readings show 34°C at the airport, while BBC Weather lists 22°C for the broader area, suggesting localized variation and the importance of the official station data [2][3]. The 100% “YES” probability likely reflects a binary contract structure where “YES” simply confirms a temperature was recorded, rather than predicting a specific range, creating a divergence between the binary market and the more granular range-based odds on Polymarket.

Traders should monitor the official Wunderground daily history for CYYZ, which serves as the resolution source, and watch for any late-day heat advisories from Environment Canada that could signal a spike above 33°C. No major weather announcements are scheduled beyond standard daily forecasts, but the settlement window closes at 12:00 UTC on 15 July, meaning the final reading must be captured before then. The key dependency is the accuracy of the Wunderground record, which aggregates data from the airport’s automated station and is the sole arbiter for this contract.

Sources: 1 · 2 · 3

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

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

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.

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.

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.