Highest temperature in Seattle on August 16?

Platform comparison

Market context

On 16 August 2026, the highest temperature recorded at Seattle-Tacoma International Airport will fall into one of several defined ranges. The market currently prices all outcomes at 0% YES, reflecting either a data-entry error or extreme illiquidity on Polygon. Settlement hinges on Weather Underground's Daily Observations table rather than the Day High & Low summary—a distinction that matters when automated feeds diverge from manual station records, which occurs roughly 2–3% of the time across US airport stations.

Seattle's August climate is remarkably stable. Historical data from 1945 onwards shows the city records temperatures above 85°F on fewer than 15 days per month, with a median high of 79°F. The 1994 heat dome pushed readings to 96°F, and the 2021 Pacific Northwest heatwave saw 108°F recorded—both outliers separated by decades. For a typical mid-August day, the 75–80°F range captures roughly 60% of historical outcomes, whilst readings above 90°F occur in perhaps 5–8% of cases. Current market pricing suggests traders either view the contract as mispriced or lack conviction on any single temperature band.

Traders should monitor the National Weather Service Seattle office forecasts released 7–10 days before settlement, which typically achieve 85% accuracy for high-temperature predictions. Upper-atmosphere patterns and ridge positioning over the Pacific Northwest drive August variability; any anomalous heat dome or marine layer persistence will shift probabilities materially. USDC liquidity on Polygon remains thin for weather contracts outside major US cities, so position sizing should account for potential slippage when closing conditional token stakes.

Methodology

This page reviews Highest temperature in Seattle on August 16? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Scam?, which mirrors the Polymarket order book at 0% fees.

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.

UK Frequently Asked Questions

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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.