Highest temperature in Wellington on July 21?

Platform comparison

Market context

The market tracks the peak Celsius temperature recorded at Wellington International Airport on 21 July 2026, with settlement tied to Wunderground’s daily history for station NZWN. Today’s live readings show 15°C with south-south-westerly winds at 24 mph and 72% humidity, conditions that typically suppress extreme heat in mid-summer [3]. Programmatic traders would model this by ingesting real-time API feeds from Wunderground or NOAA, comparing current anomalies against the 30-year July mean for NZWN, which rarely exceeds 18°C.

Historical data frames the 0% crowd-implied probability for higher ranges as rational: July in Wellington is consistently cool, with the highest recorded temperature in the month over the past decade staying below 20°C. The frontrunner outcome of 12°C at 100% probability aligns with this pattern, while “7°C or below” sits at 0%, reflecting the station’s thermal inertia and maritime moderation [2]. A bot executing conditional orders would likely short any outlier bets above 16°C, given the lack of historical precedent for such spikes in this window.

Traders should monitor the Bureau of Meteorology’s daily synoptic charts for shifts in the Tasman Sea high-pressure system, which can drive warmer air masses inland. No immediate weather announcements are scheduled, but the 24 mph wind speed suggests persistent cooling airflow that limits temperature escalation [3]. Dependencies include Wunderground’s data latency and the precise timestamp of the settlement window at 12:00 UTC, meaning last-minute cloud cover or wind shifts could alter the final reading.

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

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

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

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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.

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.