Shanghai June 25 Low Temp: 21°C at 71% Odds

A single-day temperature market in Shanghai has made up its mind fast. The 21°C outcome for the city’s lowest temperature on June 25 opened the session at 0.23 and has climbed to 0.72 inside 24 hours. That is a 17.5% swing in one trading day, and the market is now implying a 71.5% probability that Shanghai’s overnight low lands exactly at 21°C. For a market with a one-day resolution window, that kind of directional conviction is worth understanding.

The market question is straightforward: what will the lowest recorded temperature in Shanghai be on June 25, 2026? The YES contract for 21°C trades at $0.72. The NO contract, covering every other outcome from 17°C or below through 27°C or higher, trades at $0.29. The market closes at 12:00 UTC on June 25. Total volume stands at $12,442, with $9,558 of that trading in the last 24 hours.

How the Twenty-One Degree Contract Works

A YES resolution requires Shanghai’s official minimum temperature for June 25 to be recorded as exactly 21°C. The market resolves based on the designated meteorological reporting source for that date. Any other reading, whether 20°C, 22°C, or outside that range, pays the NO side.

• YES (21°C): trades at $0.72, implying 71.5% probability
• NO (all other outcomes): trades at $0.29, implying 28.5% probability

The NO contract covers a wide band of alternatives: 17°C or below, 18°C, 19°C, 20°C, 22°C, 23°C, 24°C, 25°C, 26°C, and 27°C or higher all sit on the NO side. Shanghai’s minimum temperature for June 25 misses the YES target if the overnight low dips to 20°C, nudges up to 22°C, or lands anywhere outside the 21°C mark. Given June’s typical overnight lows in Shanghai, a reading in the 20°C to 23°C range is climatologically reasonable, which is exactly what makes the 28.5% NO probability meaningful rather than trivial.

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Momentum and Market Signals

The momentum picture here is unusually sharp for a micro-duration weather market. The 1h change is flat at 0.0%, but the 24h move of plus 17.5% combined with a trend score of 48.60 signals a market that made a decisive directional move and has since stabilized at its new level. The most likely driver: traders with access to short-range Shanghai forecast models pushed the 21°C outcome hard as the forecast window narrowed and confidence in the overnight low crystallized around that specific reading.

Total volume of $12,442 is thin by prediction market standards, and the $9,558 that traded in the last 24 hours represents the bulk of all activity. Liquidity sits at $38,278, which is actually deeper than the volume suggests. That liquidity-to-volume ratio means the order book can absorb moderate new positions without large slippage, but a single large trade could still move the price noticeably. Here’s what the measurements are telling us: this market is not driven by institutional depth. It is driven by a small number of traders with a strong directional view on tomorrow’s overnight temperature.

Key Factors

• The 24h price change of plus 17.5% reflects a sharp, recent repricing toward 21°C as the forecast window tightened on June 24.
• The 1h change of 0.0% shows the market has stopped moving, suggesting traders have reached a consensus price for now.
• Total volume of $12,442 is below $1M, meaning this market can reprice sharply on a single updated weather model run or a new trade from an informed participant.
• Liquidity of $38,278 exceeds 24h volume by roughly four times, which limits but does not eliminate slippage risk on new positions.
• The trend score of 48.60 sits in a moderate range, consistent with a market that has found a resting point but has not exhausted its directional energy.

Lines Analysis: Shanghai’s June Overnight Range

Shanghai sits in a subtropical climate zone, and late June typically delivers overnight lows in the low-to-mid 20s Celsius. Historical June patterns for the city show minimum temperatures clustering between 20°C and 25°C during the last week of the month, with 21°C representing a plausible low end of that range. The market’s 71.5% probability for exactly 21°C implies traders believe current atmospheric conditions, likely influenced by a relatively cool air mass or reduced humidity compared to peak summer, are pointing toward the cooler end of the expected range for the overnight period ending June 25.

What makes the NO case real is measurement precision. Shanghai’s overnight low must land at exactly 21°C, not 20°C, not 22°C. The China Meteorological Administration reports temperatures to the nearest whole degree, but the actual reading can fall anywhere within a half-degree band. A reading of 21.4°C rounds to 21°C and pays YES. A reading of 20.5°C rounds to 21°C and pays YES. But a reading of 20.4°C rounds to 20°C and pays NO. That rounding sensitivity means the NO side retains real value even when forecasts point toward 21°C, because forecast models themselves carry plus or minus one to two degree uncertainty at 24-hour range.

Signals to Monitor

• The China Meteorological Administration’s official June 25 minimum temperature report is the single resolution-determining data point.
• Updated short-range numerical weather prediction runs from ECMWF or GFS in the hours before the overnight period would reprice this contract if they shift the expected low by one degree.
• Any significant change in Shanghai’s wind direction or cloud cover overnight on June 24 to 25 could push the actual low above or below the 21°C target.
• The 22°C and 20°C outcome contracts on this same market are worth monitoring as proxies for how informed traders are hedging around the 21°C central estimate.
• If the YES price retreats below 0.65 in the overnight session, that would signal a model update has reduced confidence in the 21°C reading specifically.

The data doesn’t care about the politics, and in a one-day temperature market, it doesn’t have time to. Total volume of $12,442 tells us this is a small, specialized market. The $9,558 in 24h volume shows a sharp directional bet was placed today, and the current price reflects that bet holding. The data favors the YES side for now, but rounding precision and forecast uncertainty keep the NO contract alive at 28.5%.

LINES VERDICT

LEAN YES, THIN MARKET

The market made a decisive move toward 21°C on June 24 and has held that level, reflecting converging short-range forecast data pointing to a cool overnight low for Shanghai on June 25. The rounding sensitivity of official temperature reporting keeps the NO side relevant, but the directional evidence favors the leading outcome.

What the market says: At 71.5% implied probability, traders are pricing 21°C as the most likely Shanghai overnight low for June 25, but thin volume below $15,000 total means this price is vulnerable to sharp movement on any updated forecast model or single large trade before the 12:00 UTC resolution on June 25.

Key unknown: The single most important data point is the final official minimum temperature report from the China Meteorological Administration for June 25. Any updated short-range forecast model run that shifts the expected Shanghai overnight low by even one degree would reprice this contract before resolution.