Highest temperature in Los Angeles on August 9?

Platform comparison

Market context

Los Angeles International Airport was hot enough on 9 August to put the contract near the top of its range, with Weather Underground’s primary settlement source expected to be the Daily Observations table rather than the headline Day High & Low summary. That matters because the market is not resolving on a citywide forecast or a generic Los Angeles reading, but on the recorded maximum at LAX within the settlement window; by the time trading is judged, the key question is whether the official daily maximum lands in the 80–81°F bin or slips elsewhere. Polymarket’s own market page currently shows 80–81°F at about 99.4% and the next outcomes at below 1%, which is materially tighter than sportsbook-style pricing would normally be for an ordinary weather event.[2]

Historically, LAX is one of the cooler major Los Angeles-area stations because coastal influence often keeps it below inland parts of the basin, so traders should read the current near-certain pricing as a station-specific call rather than a broader Los Angeles heat signal. Comparable August heat episodes have still produced sharply different outcomes across the region, with downtown and inland sites spiking much higher while LAX can remain in the low 80s; KTLA reported a recent Southern California heat burst that set or matched records at several stations, including a new LAX high of 82°F, illustrating how local microclimates can diverge even in the same weather regime.[14]

The main catalysts are the final Weather Underground observations for KLAX and any late data revisions before the first datapoint for 10 August is published, because the market rules allow changes only until that cutoff.[2] The National Weather Service’s KLAX time-series and daily climate products are the practical cross-checks traders usually watch for consistency with the settlement source, while the seven-day forecast for Los Angeles shows the broader setup that can influence expectations around late-day heating, marine layer timing, and any residual warmth into the close of observations.[11][12][13]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Los Angeles on August 9? 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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

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 Best Prediction Markets UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

What are the best prediction markets for UK traders in 2026?

For UKGC-regulated markets: Betfair Exchange (sports, politics) and Smarkets (sports, politics, lower commission than Betfair). For broader global event prediction: Polymarket (deepest liquidity, 0% fee, USDC settlement). For US-regulated option: Kalshi (USD, limited UK payment options). Most serious UK traders use a combination of Betfair for regulated sports and Polymarket for broader markets.