Highest temperature in Toronto on June 25?

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Market context

The real-world event driving this market is the highest temperature recorded at Toronto Pearson International Airport on 25 June 2026, measured in degrees Celsius. Current crowd-implied probability sits at 0% for any specific range, reflecting the uncertainty of a single day’s peak in early summer when weather patterns remain volatile.

Historically, late June in Toronto often sees highs between 22°C and 30°C, though extremes have occurred. In 2023, Pearson recorded 35.8°C, the hottest since July 2016, prompting a heat warning from Environment Canada[3]. Conversely, June 25, 2022, saw a record-low high of 22.9°C for that date since 1938, illustrating the wide swing possible[8]. These cases suggest that while 0% probability may seem definitive, it overlooks the historical volatility that could push temperatures into higher ranges.

Traders should monitor Environment Canada’s daily forecasts and any emerging heat advisories, as these directly influence peak temperatures. Recent news highlights a heat warning issued for the Greater Toronto Area, with officials recommending outdoor activities be scheduled during cooler parts of the day[3]. Programmatically, one would parse Wunderground’s hourly data for CYYZ, flagging spikes above 30°C, and cross-reference with real-time alerts from Environment Canada to anticipate shifts. The settlement window closes at 12:00 UTC on 25 June 2026, leaving little margin for late corrections.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Toronto on June 25? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Polymarket Review UK — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

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 Polymarket Review UK, 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?

Polymarket Review UK 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Review UK triggers a quick verification flow that finishes in minutes.