Highest temperature in Toronto on June 25?

Platform comparison

Active sub-markets

Market context

The real-world event is the peak daily temperature recorded at Toronto Pearson International Airport on 25 June 2026, which will determine the settlement of the prediction market. Current crowd-implied probability suggests a 0% chance for the "YES" outcome, while Polymarket data indicates the market assigns a 100% probability to the 20°C range[1]. This stark divergence in implied probability versus decimal odds framing highlights how platforms like Polymarket (using implied probability) differ from Kalshi or Betfair (using decimal odds), where traders must convert between formats to assess true value. Fee structures also vary significantly; Polymarket often offers lower fees but requires KYC for larger withdrawals, whereas Smarkets charges a commission on winnings but allows more flexible access.

Historical data frames the current 0% probability as highly conservative, given that June 25 has previously recorded a low of 22.9°C, the highest low for that date since 1938[9]. AccuWeather forecasts for June 2026 at Pearson show daily highs ranging from 76°F to 94°F (approximately 24°C to 34°C), with an average high of 85°F (29°C)[2]. This historical precedent suggests that temperatures in the 20°C range are plausible, making the 0% market probability an outlier that traders should scrutinise against platforms like Kalshi, which may offer more liquid markets for temperature events.

Traders should monitor Environment Canada heat warnings and daily forecast schedules, as recent extreme heat events in the Greater Toronto Area have pushed temperatures to 33–36°C with humidex readings up to 46[3]. The Weather Network’s national forecast for 25 June 2026 will be a critical catalyst, as any deviation from the average 29°C could shift market sentiment[7]. Divergence in KYC requirements between platforms like Polymarket and Betfair may also affect liquidity, with some traders preferring platforms that offer faster access without stringent verification.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Toronto on June 25? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

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 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.

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.