Wellington July 16 High: Will Sixteen Degrees Hold?

Wellington’s weather market is running hot on data and cool on certainty. The 16°C outcome carries a 56.5% implied probability heading into resolution tomorrow, but a sharp 11% price drop over the past 24 hours signals that traders are not settled. Here’s what the measurements are telling us: midwinter Wellington temperatures cluster tightly, and a one-degree miss in either direction is entirely plausible.

The market question asks for the highest temperature in Wellington on July 16, resolving at 12:00 NZST on 2026-07-16. The 16°C outcome sits at $0.57 YES and $0.44 NO. Total trading volume has reached $63,283, with $44,965 traded in the last 24 hours alone, suggesting active repositioning as forecast models update.

How the Wellington Temperature Contract Works

This market resolves on a single outcome: the highest recorded temperature in Wellington on July 16. The winning outcome pays out; all others lose. Eleven discrete outcomes are available, ranging from 10°C or below up to 20°C or higher. Resolution is determined by the market’s designated data source for Wellington daily maximum temperature.

• 16°C YES trades at $0.57, implying a 56.5% probability of the daily maximum landing exactly at 16°C.
• 15°C and 17°C are the nearest alternatives, absorbing much of the remaining probability mass as adjacent outcomes.

The NO side here is not a single condition but a collection of eleven alternatives. Wellington’s July daily maximums historically range from 11°C to 17°C, with the median sitting around 13°C to 14°C. For the 16°C outcome to miss, temperatures must land at 15°C or below, or 17°C or above. July 2026 has seen a mild Southern Hemisphere winter pattern, which slightly favors the upper end of the typical range, but marine airflow from the Cook Strait regularly pulls Wellington’s peak readings back toward the mid-teens.

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Momentum and Market Signals

The composite momentum signal is bearish for the 16°C outcome. The 1-hour change of -1.5% and 24-hour change of -11.0%, combined with a trend score of 48.63, suggest traders are rotating probability toward adjacent outcomes, most likely 15°C as cooler air advection models gain traction in the 24 to 48 hour forecast window. This kind of mid-range trend score often reflects genuine forecast uncertainty rather than directional conviction.

Total volume of $63,283 is modest. The $44,965 traded in the last 24 hours represents a substantial portion of total activity, confirming that this market is actively traded but not deeply capitalized. Liquidity stands at $135,940, which is healthy relative to volume and means individual trades are unlikely to move the price dramatically. Still, with volume well below $1 million, a single large position could shift the 16°C price by several percentage points before resolution.

• The 1-hour price change of -1.5% and 24-hour change of -11.0% together point to softening confidence in 16°C, likely driven by updated numerical weather prediction output for Wellington.
• The trend score of 48.63 sits just below neutral, confirming the market has not committed firmly to any adjacent outcome yet.
• Liquidity of $135,940 relative to $63,283 total volume indicates the order book is well-supported for a market of this size.
• Volume concentration in the last 24 hours suggests active repositioning, not stale prices.
• The 15°C and 17°C outcomes are the most likely beneficiaries if 16°C continues to lose probability.

Lines Analysis: Wellington on July Sixteen

Wellington’s midwinter climatology supports the 16°C outcome as a reasonable modal forecast. The city’s July daily maximums are heavily influenced by northwesterly foehn events, which can push temperatures briefly into the 16°C to 18°C range even in the coldest month. A persistent high-pressure system over the Tasman Sea during the first half of July 2026 has kept temperatures above the long-run July median. The 16°C outcome is not a stretch under those conditions. The data doesn’t care about the politics of forecasting: foehn or northwest flow on July 16 gets Wellington to 16°C.

The barrier to the 16°C outcome is a southerly change. Wellington’s notorious southerlies arrive quickly and drop maximum temperatures to the 11°C to 14°C range within hours. Meteorological models showing a trough passage on July 15 to 16 would shift probability mass downward toward 13°C, 14°C, or 15°C outcomes. The 11% 24-hour price drop suggests at least some forecast models are now showing that risk. A confirmed southerly arrival before noon NZST on July 16 would essentially eliminate the 16°C outcome.

• MetService New Zealand’s 48-hour forecast for Wellington is the single most important data point before resolution. Any southerly trough timing update reprices every outcome simultaneously.
• Foehn wind persistence through the morning hours of July 16 would support 16°C or higher outcomes.
• GFS and ECMWF model agreement on the trough timing would confirm or deny the bearish momentum signal from the last 24 hours.
• The 15°C outcome is the most direct competitor; watch its price for real-time market consensus on forecast models.
• A calm, overcast day without strong advection favors 14°C to 15°C, the most common Wellington July outcome type.

Total volume of $63,283 is sufficient for price discovery but thin enough that late forecast model runs could produce sharp price moves in the final hours before resolution. The data currently leans toward 16°C as the modal outcome, but the 11% 24-hour drop is a genuine signal that adjacent outcomes are gaining ground. The market is pricing uncertainty, not science. The outcome depends entirely on whether a southerly reaches Wellington before the daily maximum is recorded.

LINES VERDICT

MARGINAL FAVORITE, SHRINKING LEAD

The 16°C outcome holds the highest single-outcome probability, but the momentum signal is clear: traders have been moving away from it for 24 hours, and the most likely driver is an incoming southerly change. Wellington’s weather resolves fast, and so will this market.

What the market says: The 56.5% implied probability means the market rates 16°C as the most likely single outcome, but with eleven alternatives, a 57-cent contract carries real risk. Volatility will spike in the final hours before the 2026-07-16 12:00 resolution as the last model runs arrive.

Key unknown: The timing and intensity of any southerly wind change reaching Wellington before noon NZST on July 16 is the single variable that will determine whether 16°C holds or the probability mass collapses into the 13°C to 15°C range.