Highest temperature in Houston on August 9?

Platform comparison

Market context

Houston’s high on 9 August is the relevant event, and the market is being settled off the highest Fahrenheit reading in Weather Underground’s Daily Observations for William P. Hobby Airport, not the summary high shown elsewhere. The crowd-implied **0% YES** looks markedly below the surrounding weather tape: AccuWeather’s Houston August outlook has the 9 August high at **92°F**, the National Weather Service had **92°F** for the day, and Weather Underground’s own front-page conditions on the morning of 9 August also showed **92° / 79°**[1][7][8][9].

Historically, Houston’s early-August highs often sit in the low 90s, with the climate normal for this date at **94°F** and a record of **105°F**, so a result in the low-to-mid 90s would be unremarkable rather than a tail event[12]. That makes the current **0% YES** difficult to square with either modelled or observed conditions, and it sits well below what a typical market would imply for a near-certain hot August day. No sportsbook line was available in the supplied results, but the weather forecasters and Weather Underground snapshot all point to a high around the low 90s rather than anything materially cooler[1][7][8][9].

For traders, the decisive catalyst is the final Daily Observations entry for Hobby Airport as it appears on Weather Underground, since that is the settlement source and the contract explicitly prioritises that table over the summary panel. The main dependency is whether any late-day convection or cloud cover suppresses the maximum before the reporting cutoff; NWS Houston/Galveston had already flagged only a chance of thunderstorms with a **92°F** high and **79°F** overnight low, which leaves limited room for a surprise but enough for a one- or two-degree swing if storms materialise[8][12].

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

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.

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 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 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.