Highest temperature in Toronto on May 25?

Platform comparison

Active sub-markets

Market context

Toronto's weather on 25 May 2026 will be measured against historical May patterns for the city, where late-spring temperatures typically range between 18–24°C at Pearson International Airport. The current 0% probability assigned to this market suggests traders are pricing in expectations well below what historical records indicate as plausible for that date. May 25th falls near the tail end of spring, when Toronto regularly experiences warm afternoons following the transition from April's cooler conditions.

Comparable May 25th observations from Environment Canada's records show Toronto has recorded highs between 20–28°C on this specific date across recent decades, with occasional outliers reaching 29–30°C during warmer years. The 0% probability implies the market is either heavily discounting the possibility of any temperature outcome, or traders are awaiting clarity on which specific temperature range the market will settle into. This disconnect between historical variability and current pricing warrants attention from those tracking seasonal weather patterns.

The settlement window closes at midday on 25 May 2026, giving traders a narrow window to adjust positions once morning forecasts become available. Environment Canada's extended forecasts, typically released 10–14 days in advance, will provide the first substantive signals about whether late-May conditions favour above or below seasonal norms. Traders should monitor atmospheric pressure systems and jet-stream positioning in the week prior, as these drive whether warm air masses reach southern Ontario or cooler systems dominate.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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?

On PolyGram, which mirrors the Polymarket order book at 0% fees. 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.

What does it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.