Highest temperature in Los Angeles on August 9?

Platform comparison

Market context

Los Angeles International Airport’s highest temperature on 9 August 2026 was read from the Weather Underground daily observations table, so the relevant question is whether the airport ever climbed out of the 80–81°F bin rather than what the summary box showed. On the available market page, the contract is already priced as a near-lock at **80–81°F** with about **99.4%** implied probability, while the other bins are effectively unpriced; that leaves little visible spread for a sportsbook-style comparison, but it does create a clear gap versus any analyst view that treats the event as settled only after the official table is finalised.[2][11]

The historical frame points the same way: late-summer Los Angeles highs are often clustered in the upper 70s to low 80s at the coast, while hotter inland readings can diverge sharply and are not decisive for this contract because it resolves only on LAX. Time and Date’s historic Los Angeles page shows 9 August conditions around the low 80s, and the National Weather Service climate and time-series products for KLAX are the more relevant benchmarks for how the airport behaves on a warm August day.[3][11][13] By contrast, the broader regional heat coverage from ABC7 and KTLA underscores that inland stations can post much higher numbers during heat events, which matters for headlines but not for this specific resolution source.[5][14]

The main catalyst for traders is not a new forecast but the publication and any subsequent revision of the KLAX observations in the official archive, because the market rules allow corrections until the first datapoint for the next date is posted.[2] That means the only meaningful dependency is whether the Weather Underground table ultimately records a maximum above 81°F; once the next day’s first observation is in place, later edits should not alter settlement.[2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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.

FAQ

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi vs Polymarket trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.