Highest temperature in Toronto on August 12?

Platform comparison

Market context

On 12 August 2026, Toronto Pearson International Airport will record a daily maximum temperature in Celsius. The market resolves to whichever temperature band contains the highest reading logged in Weather Underground's Daily Observations table between midnight and the settlement window closure at 12:00 UTC. This specification matters: the platform explicitly prioritises granular observation data over the summary "Day High & Low" figure, a distinction that occasionally produces divergent outcomes when station equipment logs micro-fluctuations or timing misalignments occur.

Toronto's August climate presents a narrow historical band. Over the past three decades, the city's peak August temperatures have clustered between 26–28°C on typical days, with extremes reaching 31–33°C during heat domes. The 1975 record of 37.8°C remains an outlier; recent decades show a median August high near 26.5°C. Current crowd probability sitting at 0% suggests traders are pricing in either a specific temperature threshold deemed climatically implausible or genuine uncertainty about which band the market operator has selected for resolution brackets.

Traders should monitor Environment and Climate Change Canada's seasonal forecasts through spring 2026, particularly any signals of anomalous high-pressure systems or jet-stream positioning that could drive late-summer heat events across Ontario. The National Weather Service's 30-day and extended outlooks, published monthly, will offer the clearest early signals. Cross-platform comparison shows minimal activity on equivalent Kalshi weather contracts for Toronto; sportsbooks do not typically offer temperature-specific wagers, leaving prediction markets as the primary price discovery mechanism for this event.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.