Highest temperature in Singapore on July 8?

Platform comparison

Market context

The real-world event hinges on whether Singapore Changi Airport will record a peak temperature of 31°C or higher on 8 July 2026, a threshold the current crowd has dismissed with a 0% implied probability for a "YES" outcome. This zero valuation suggests the consensus believes the day will remain firmly within the typical tropical band, likely capped by the maritime influence that historically prevents extreme heat spikes in equatorial cities.

Historical data frames this probability as a clear underdog bet for the 31°C+ range. Summer averages at Changi hover around 88°F (31.1°C), rarely dipping below 84°F or exceeding 92°F, meaning the 31°C mark sits right at the median rather than the extreme tail [5]. While heat domes can break records in tropical zones, maritime cooling in Singapore has kept its absolute high near 97°F (36.1°C), making a sudden jump to a sustained 31°C+ peak on a single day statistically unlikely without a specific weather anomaly [6]. The 0% crowd-implied probability likely overreacts to the typical thundery showers forecast for Wednesday, which usually suppress peak temperatures [2].

Traders should monitor the immediate forecast for thundery showers and light southerly winds, which act as the primary catalysts keeping temperatures down [2]. The National Weather Service confirms steady pressure at 1006mb, a condition that typically maintains stable, non-extreme thermal profiles [3]. If the morning rain mentioned in the 10-day forecast fails to materialise or if winds shift to a hotter, drier direction, the value spot for the 31°C+ range could emerge as a contrarian angle against the current zero valuation [4]. The settlement window ending in 2026 allows ample time for such anomalies to develop, suggesting the current consensus may be too rigid.

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

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.

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.