Highest temperature in San Francisco on August 13?

Platform comparison

Market context

San Francisco's weather on 13 August 2026 will be measured against historical August patterns, with the highest temperature recorded at SFO International Airport determining settlement. The 0% crowd probability suggests traders are pricing in either extreme confidence in cooler conditions or minimal participation; August typically sees highs in the mid-60s Fahrenheit at the airport, though marine layer influence can suppress readings compared to inland Bay Area stations.

Historical August data from Weather Underground shows SFO rarely exceeds 75°F, with the airport's coastal location and persistent fog keeping temperatures well below regional averages. The last decade of August records indicates a clustering around 62–68°F for daily highs, establishing a baseline against which any deviation would signal unusual atmospheric conditions. Traders should note that the resolution mechanism explicitly prioritises the Daily Observations table over summary figures, eliminating ambiguity around measurement timing or station drift.

Catalysts affecting August 2026 conditions include Pacific high-pressure systems, which typically dominate the season but can vary in intensity year to year, and any anomalous warming patterns linked to broader North Pacific sea-surface temperatures. Current NOAA seasonal outlooks and real-time SST anomaly data will inform whether conditions favour above or below-average temperatures. The settlement window closes at 12:00 UTC on 13 August, aligning with standard market convention; traders holding positions should monitor SFO weather station data directly through Weather Underground's Daily Observations feed to verify resolution criteria ahead of settlement.

Methodology

This page reads Highest temperature in San Francisco on August 13? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed alongside for venue context. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

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%.