Highest temperature in Seattle on July 23?

Platform comparison

Market context

Polymarket is pricing this Seattle heat contract at **0% YES**, so the market is effectively assigning no weight to a July 23 peak that lands in the resolved target range. Because settlement uses the highest temperature recorded at Seattle-Tacoma International Airport on that date, the trade is about the day’s intraday maximum rather than the noon reading or the daily average, and the tokenised position on Polygon settles in USDC through conditional tokens once the Wunderground history page is checked.

That zero price sits against Seattle’s usual July profile, where average highs are in the low to mid-70s Fahrenheit and nights are much cooler. Historical climate guides put Seattle’s typical July high around 73–75°F, with only modest rainfall and long daylight hours, which means the market is not asking whether it will be pleasant, but whether the airport observation will spike enough to break into the listed bracket.[1][4] In that sense, 0% implies traders see the current contract terms as unusually unlikely relative to a normal summer day, even before accounting for the exact range used for resolution.

For a hands-on Polymarket user, the main catalysts are the same ones that move local forecast risk: National Weather Service guidance for Sea-Tac, any late heat build-up in the Pacific Northwest, and the possibility of a brief warm surge that lifts the airport maximum above nearby city forecasts. The NOAA timeseries for KSEA is the closest live reference point for monitoring trend changes before the Wunderground settlement check, while the market’s final outcome depends on the single highest reading recorded that day at Sea-Tac rather than broader Seattle conditions.[2]

Sources: 1 · 2 · 3 · 4

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

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 PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.