Highest temperature in Seattle on August 10?

Platform comparison

Market context

Seattle's weather on 10 August 2026 will be measured against historical summer patterns for the Pacific Northwest, where afternoon highs typically range between 75–85°F during mid-August. The market's 0% implied probability suggests traders expect the highest temperature to fall below the lowest threshold offered, though the specific range boundaries are not disclosed in available documentation. Resolution will depend on the highest reading from Weather Underground's Daily Observations table at Seattle-Tacoma International Airport, with that source taking precedence over summary figures if discrepancies arise.

August temperatures in Seattle show considerable year-to-year variation. The National Weather Service records indicate that extreme heat events—temperatures exceeding 90°F—occur irregularly in the region, with notable spikes in 2021 and 2023. Comparable prediction markets on weather platforms like Kalshi and Betfair have historically seen low probability assigned to outlier temperature outcomes, though decimal odds formats on European books sometimes reveal sharper pricing than implied probabilities suggest. The current 0% reading likely reflects baseline expectations rather than genuine impossibility.

Traders monitoring this market should track mid-summer weather pattern forecasts released in late July 2026, particularly ridge-building systems that occasionally drive heat into the Pacific Northwest. NOAA's Climate Prediction Center issues monthly outlooks that influence longer-dated weather derivatives. The settlement window closes at midday on 10 August, meaning real-time temperature readings will determine final resolution. Cross-platform comparison shows Polymarket's fee structure and Smarkets' decimal odds framework may price tail outcomes differently, creating potential arbitrage opportunities for traders comparing identical underlying events across venues.

Methodology

We read Highest temperature in Seattle on August 10? 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 mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

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

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Robinhood Prediction Markets has a different geo footprint and routes to Polymarket's order book at 0% fees.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Robinhood Prediction Markets offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.