Highest temperature in Toronto on August 2?

Platform comparison

Market context

Toronto Pearson’s **highest temperature** on 2 August will be the settlement print that decides the market, and the relevant comparison is not the citywide forecast headline but the station-day extreme captured by Wunderground for CYYZ. Toronto’s early-August climatology is warm but not usually extreme: long-run August highs are around the mid-20s °C, with the 2 August normal maximum near 26.7 °C and the record for that date at 33.9 °C in the Toronto historical series.[2][15]

That framing is why a **0% YES** crowd price can coexist with a live weather market: if the range bands are calibrated above a routine summer high, the event only pays if the airport reaches an unusual heat spike, not merely a pleasant afternoon. For context, Toronto’s all-time heat record is 40.6 °C, but those upper-tail events are rare and usually require a strong continental ridge and very dry, sunny conditions.[11][8] Programmatically, a bot should treat this as an event-time scrape problem rather than a generic forecast: poll the Wunderground history page, read the daily maximum for Toronto Pearson, convert to the market’s Celsius bands, and watch for late-day updates rather than relying on the morning forecast alone.[10]

The main catalysts are short-horizon meteorological, not calendar-based: cloud cover, precipitation timing, wind direction, and any shift in the air mass over southern Ontario through the daytime heating window. Environment and Climate Change Canada provides station-history data access and downloadable daily records, which is useful for cross-checking any automated monitor against another source if Wunderground lags or changes formatting.[1] If you are wiring conditional orders or a copy-trading rule, the practical trigger is whether forecast highs and observed hourly temperatures drift towards or away from the settlement band before the day’s maximum is set.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Toronto on August 2? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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 Polymarket Bot UK. 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 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 Polymarket Bot UK 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.