Highest temperature in Los Angeles on August 17?

Platform comparison

Market context

Polymarket has this contract at 0% YES, implying the market is treating a Los Angeles high in the settled Weather Underground band as effectively ruled out. For August in Los Angeles, that is a sharp view: the station at LAX usually sits in the upper 70s by climatology, and the market’s current pricing suggests traders are leaning hard towards a cooler reading staying put through the settlement cutoff.

Historical read-through matters because LAX often runs below inland Los Angeles on hot days, with marine influence keeping extremes contained even when the wider region warms. That makes a late-day spike less likely than at valley stations, and it explains why a zero-priced outturn can persist if the Daily Observations table has already logged a maximum in the mid-to-high 70s. On Polymarket, that means USDC is already backing conditional tokens as though only a narrow temperature bin remains credible.

The key catalyst is the Weather Underground Daily Observations table itself, not the summary high/low box, because the market resolves from that table if the two disagree. Traders should watch the final observation roll-up for 17 August and any station updates before the next date’s first datapoint, since revisions within the window can still matter. Recent local coverage also pointed to a brief Southland warm-up earlier in the month, but forecast nudges of a few degrees are not the same as an observed airport maximum, and the contract settles only on the recorded LAX figure.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Los Angeles on August 17? 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.

UK Frequently Asked Questions

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 Scam?. 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.

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%.