Highest temperature in Toronto on June 25?

Platform comparison

Active sub-markets

Market context

The real-world event hinges on whether Toronto Pearson International Airport records a high temperature above 36°C on 25 June 2026, a threshold that currently carries a crowd-implied probability of zero per cent. Historical data frames this improbability: June 25 has never seen a high exceeding 36°C at this station since records began in 1938, with the highest low on that date being 22.9°C just this year [9]. While an extreme heat event recently pushed temperatures to 35.8°C in the Greater Toronto Area, that peak occurred under a specific heat warning and did not breach the 36°C mark on this calendar date [3][8]. The 0% probability reflects the statistical rarity of such an extreme spike in late June, where average highs typically range between 21°C and 24°C [1][2].

Traders should monitor Environment Canada’s daily heat warnings and the National Weather Service’s real-time dew point charts for CYYZ, as rising humidex values often precede temperature spikes [3][4]. A recent forecast indicates June 2026 highs will range from 20°C to 28°C (68°F to 83°F), making a breach of 36°C highly dependent on an unforecasted atmospheric anomaly [7]. When comparing platforms like Polymarket versus Kalshi or Betfair, note that Polymarket displays decimal odds while Kalshi uses implied probability, which can obscure the true risk of this zero-per-cent event for casual users. Fee structures also diverge; Polymarket offers lower fees but requires KYC for larger withdrawals, whereas Kalshi’s US-centric model imposes stricter identity verification, potentially limiting access for international traders researching this specific weather outcome.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Toronto on June 25? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On Kalshi Alternative 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?

Kalshi Alternative 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.

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.