Shanghai June 21 Low: 23°C at 53% as Traders Converge

The 23°C outcome just posted a 17% surge in 24 hours on this Shanghai overnight low market, and the timing is not random. Traders are pricing a very specific meteorological window: the lowest temperature Shanghai records on June 21, 2026. The implied probability now sits at 53%, which means the market sees this as a coin flip leaning toward 23°C. That lean has grown sharply overnight.

The market question asks: what will the lowest temperature in Shanghai be on June 21? The YES contract on 23°C trades at 0.53, the NO contract at 0.47, with resolution set for June 21, 2026 at 12:00 UTC. Total volume across the contract is $5,950, with $5,216 of that moving in the last 24 hours alone.

How the Twenty-Three Degree Contract Works

YES pays out if Shanghai’s official recorded low temperature on June 21 equals exactly 23°C. The China Meteorological Administration (CMA) and its Shanghai regional stations provide the authoritative measurement. The contract resolves June 21, 2026. Alternative outcomes include 22°C, 24°C, 21°C, 25°C, 20°C, and ranges at both extremes (19°C or below, 29°C or higher).

• YES (23°C lowest temp on June 21): 0.53 implied probability, 53%
• NO (any other temperature): 0.47 implied probability, 47%

The NO contract pays when Shanghai’s recorded low falls outside 23°C, whether that is a cooler 22°C or 21°C, or a warmer 24°C or 25°C. Shanghai sits in the middle of its plum rain season in late June, when overnight temperatures typically cluster between 22°C and 25°C. A shift in the rain band, a surge of subtropical moisture, or an unexpected cold trough from the north could push the low outside the 23°C window. The CMA’s regional station network captures the official figure used for resolution.

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Momentum and Market Signals: Sharp Move, Thin Book

The combined momentum signal is clear and recent. The 1-hour price change of +6.0%, the 24-hour change of +17.0%, and a trend score of 59.83 all point in the same direction: traders added conviction on the 23°C outcome within the last day. That move likely tracks updated short-range weather model output for the June 20 to 21 overnight period over Shanghai.

Total volume is $5,950 with $5,216 trading in the last 24 hours. Liquidity stands at $29,205 in the order book. Because total volume is well below $1 million, this market can reprice dramatically on a single large trade or a fresh forecast update from CMA or international models. The liquidity depth relative to volume suggests professional market makers are present, but retail flow is dominating direction.

• The 24-hour price surge of 17% on the 23°C contract reflects fresh meteorological signal, not speculative noise, given the short resolution window.
• The 1-hour move of 6% shows momentum has not stalled as of the June 20 writing date.
• Total volume below $1 million means a single informed trade of a few hundred dollars can shift the price meaningfully before resolution.
• Liquidity at $29,205 is healthy relative to volume, suggesting the book will absorb moderate trades without extreme slippage.
• The trend score of 59.83 is moderately bullish on 23°C, not extreme, which is consistent with genuine meteorological uncertainty at this range.

Lines Analysis: Shanghai’s June Low and the Temperature Band

Shanghai’s overnight low on June 21 historically sits between 22°C and 25°C during the plum rain season. The 23°C outcome occupies the core of that historical range. If current synoptic conditions place a rain band over the Yangtze Delta overnight, evaporative cooling can anchor the low near 23°C. The recent +17% surge in YES price suggests updated model runs are supporting this exact outcome.

The primary risk to the 23°C outcome is directional drift. A warmer-than-expected southerly flow could push the low to 24°C or 25°C, both of which have meaningful implied probability in the alternative outcome contracts. A stalled cold front from northern China could bring the low to 22°C or lower. Shanghai’s June temperatures are volatile within a narrow band, and a 1°C miss resolves the contract to NO. The CMA’s final official station reading is the only number that matters.

• Watch CMA’s 24-hour forecast for Shanghai issued on June 20 evening for overnight low guidance.
• International model consensus (ECMWF, GFS) for the June 20 to 21 overnight period in the Yangtze Delta is the strongest real-time signal.
• Any shift in the plum rain front position will change the overnight low band by 1 to 2 degrees.
• A sustained southerly low-level jet would push the low warmer, toward 24°C or 25°C.
• A convective system clearing overnight could allow radiative cooling, pulling the low toward 22°C or 21°C.

The data favors 23°C at 53%, but a 1°C range on either side holds meaningful probability. Total volume of $5,950 makes this a thin market. The meteorological signal is the only signal that matters here, and the next CMA model update is the key data point before resolution.

LINES VERDICT

MARGINAL YES LEAN ON SEASONAL NORMS

The 23°C outcome sits at the center of Shanghai’s historical June overnight low range, and the recent momentum surge reflects real meteorological information entering the market ahead of resolution.

What the market says: At 53% implied probability, the market assigns 23°C a slight edge over all other outcomes combined, but this is a genuinely uncertain call with less than 36 hours to resolution. Thin volume means the price can move sharply on any updated forecast before June 21 at 12:00.

Key unknown: The China Meteorological Administration’s final overnight low forecast for Shanghai on June 21, combined with the position of the plum rain band, is the single data point that will reprice this contract before resolution.