Highest temperature in Toronto on June 25?

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Active sub-markets

Market context

The real-world event driving this market is the recorded high temperature at Toronto Pearson International Airport on 25 June 2026, with current data suggesting a high near 25°C under partly cloudy skies and thundery showers. Historical patterns for late June in Toronto show daily highs typically ranging between 20°C and 26°C, with the 2026 date recording a notably high low of 22.9°C—the highest such low on 25 June since 1938[10]. Recent extremes include a record-breaking 35.8°C at Pearson in July 2026, confirming that heatwaves can push temperatures well above the 20°C market frontrunner, yet the current 0% probability for any outcome above 20°C appears inconsistent with both seasonal norms and recent volatility[1][4].

Traders should monitor Environment Canada’s heat warnings and Wunderground’s hourly updates for 25 June, as thundery showers and gusty west winds at 20 km/h could suppress peak temperatures or cause rapid fluctuations[2][3]. The settlement depends entirely on the highest temperature recorded at any time on that day, meaning even brief spikes above 20°C—common during sunny intervals before showers—would invalidate the current 99% confidence in 20°C[1][3]. No official announcements have yet confirmed a heat dome for 25 June, but the absence of a forecasted extreme heat event does not rule out transient highs, especially given Pearson’s recent record lows and the city’s tendency for sudden summer temperature swings[4][10].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Toronto on June 25? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 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.