Shanghai Lowest Temp May 29: Will 21°C Hold?

Shanghai’s overnight temperature forecast for May 29 has traders split almost perfectly down the middle. The 21°C outcome is trading at 47.5% implied probability, meaning the market treats this as a genuine coin flip between adjacent degree bands. That’s not indecision. That’s the market pricing the natural variance in overnight lows that meteorological models struggle to nail within a single degree.

The market question asks: what will the lowest temperature in Shanghai be on May 29? The 21°C outcome is priced at 0.48 YES against 0.53 NO, resolving at noon UTC on May 29, 2026. Total volume stands at $5,263, with $4,047 of that traded in the last 24 hours.

How the 21°C Contract Works

YES pays out if Shanghai’s verified minimum temperature on May 29 lands exactly at 21°C. NO pays out if the overnight low falls on any other value: 20°C, 22°C, 19°C, 23°C, or any degree outside that band. The resolution source is the market itself, based on official temperature records for Shanghai on that date.

• YES (21°C lands): priced at 0.48, implying 47.5% probability.
• NO (any other reading): priced at 0.53, implying 52.5% probability.

The NO side doesn’t require a dramatic weather event. Shanghai’s minimum temperature missing 21°C by even one degree in either direction settles this contract against YES holders. In late May, Shanghai’s overnight lows typically cluster in the 18°C to 24°C range, and the spread across the listed outcomes reflects exactly that distributional uncertainty. The market is spreading probability across at least eleven listed outcome buckets, so 47.5% for any single degree band is actually a strong lean.

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Momentum and Market Signals

The momentum composite here is notable. The 1h change is flat at 0.0%, but the 24h change is plus 16%, and the trend score sits at 55.54. That combination points to a burst of conviction earlier in the 24-hour window, followed by a pause. The most likely driver: updated short-range weather model runs for Shanghai on May 28 shifted the probability mass toward 21°C, then stabilized as forecasts converged.

Total volume of $5,263 is thin. The $4,047 traded in the last 24 hours is the bulk of all activity, suggesting this market was largely dormant until traders got fresh forecast data. Liquidity is actually deep at $84,942, which means a meaningful bet could move the price sharply without much resistance on the order book. Thin volume on deep liquidity is a setup where a single informed trader with current weather data can reprice this contract fast.

Key Factors

• The 24h price move of plus 16% reflects concentrated buying of the 21°C outcome as short-range models updated, not broad market consensus.
• The 1h flatline suggests the initial catalyst has been absorbed and the market is waiting for the next forecast update cycle.
• At $5,263 total volume, this market’s price is easy to move. New weather data or a single large trade can shift the implied probability by 5 to 10 percentage points immediately.
• Shanghai’s late-May climatology places overnight lows most frequently between 19°C and 23°C, making adjacent buckets genuine competitors for probability mass.
• The trend score of 55.54 confirms mild bullish momentum for the 21°C outcome, but not a strong directional conviction signal.

Lines Analysis: Shanghai Overnight Low on May 29

The case for 21°C landing comes down to where the short-range models are pointing right now. The 16% price move in 24 hours signals that traders with access to updated numerical weather prediction output moved capital into this bucket. Shanghai’s overnight lows in late May are influenced by whether a maritime air mass is pushing inland from the East China Sea, and 21°C sits comfortably in the range that corresponds to a mild, partly cloudy night with light southeasterly flow. If current model consensus is pointing to that setup, the 47.5% probability is defensible.

What makes NO real is the same distributional spread that makes single-degree temperature markets inherently uncertain. A slightly stronger low-pressure system pushes the minimum to 20°C. A warmer southerly surge lifts it to 22°C or 23°C. Shanghai’s urban heat island adds another layer of variance between official station readings and model output. The measurement itself, depending on which station is used for resolution, can land a degree off from the dominant forecast. None of these scenarios require unusual weather. They just require the atmosphere to behave like the atmosphere.

Signals to Monitor

• The 12-hour and 6-hour forecast updates from China Meteorological Administration for Shanghai on May 29 will be the sharpest repricer of this contract before resolution.
• A shift in synoptic pattern overnight on May 28 into May 29, particularly any frontal boundary moving through the Yangtze Delta, would push probability mass toward cooler buckets like 19°C or 20°C.
• A strengthening southerly flow from the East China Sea overnight would push mass toward 22°C or 23°C and reprice 21°C lower.
• Because liquidity is deep but volume is thin, watch for any single large order that moves the YES price above 0.55 or below 0.40. That would signal an informed trader acting on updated forecast data.
• The resolution timestamp is noon UTC on May 29. The overnight low will already be set by then. Last-minute trading after the low is recorded but before resolution closes can produce sharp price convergence.

Total volume at $5,263 is thin enough that this market’s price reflects a handful of traders, not crowd wisdom. The data favors neither side with conviction. The 21°C bucket has a strong plurality of the probability, but with ten-plus competing outcome buckets, 47.5% is the ceiling for any single degree in a distribution this wide. The market is pricing uncertainty correctly here.

LINES VERDICT

LEAN YES, LOW CONVICTION

The 21°C outcome has earned its position as the plurality favorite through recent forecast-driven buying, but single-degree temperature markets in a wide distribution are structurally difficult to hold. The data is pointing to 21°C as the modal outcome, but the margin is thin.

What the market says: At 47.5% implied probability, the market treats 21°C as the most likely single outcome but acknowledges that adjacent temperature bands are genuine alternatives. The May 29 resolution deadline means there is no time for this price to recover from a model shift. Any updated forecast pushing the overnight low toward 20°C or 22°C will move this contract sharply before close.

Key unknown: The final short-range forecast update from China Meteorological Administration for Shanghai’s overnight low on May 28 into May 29 is the single data point that will reprice this contract. If that output converges on 21°C, YES firms. If it diverges toward adjacent bands, probability mass redistributes fast.

Scientific Context

Shanghai sits at approximately 31 degrees north latitude, placing it in a humid subtropical climate zone. Late May marks the transition toward the plum rain season, when moisture from the western Pacific begins to dominate. Overnight lows in this period are sensitive to the position of the subtropical high and the strength of southerly flow off the East China Sea. A single-degree temperature market in this meteorological window is trading real atmospheric variance, not noise. The spread of outcomes from 18°C to 28°C or higher in this contract reflects the genuine range of possible overnight readings during a climatologically variable period.

What moves price before the May 29 resolution: Any 6-hour or 12-hour forecast update from China Meteorological Administration or a major global model ensemble shifting the expected overnight low by even one degree will reprice this contract immediately. Given the thin volume and deep liquidity, informed traders acting on fresh model output are the primary price-moving force here.

Will 21°C land as Shanghai’s overnight low on May 29?

The market prices it at 47.5% implied probability, reflecting its status as the single most likely outcome in a wide distribution. That’s a meaningful lean, not a certainty.

What does NO mean for this contract?

Any temperature reading other than exactly 21°C resolves this contract NO. That includes 20°C, 22°C, and every other listed outcome. The atmosphere doesn’t need to do anything unusual to produce a NO result.

What data would move this price before resolution?

Updated short-range forecasts from China Meteorological Administration or global model ensembles pointing to a different overnight low would shift probability mass immediately. The 24h move of plus 16% already shows how fast forecast data reprices this market.

When does this contract resolve?

Resolution is set for May 29, 2026 at noon UTC. The overnight low will already be recorded by that point, which means late-stage trading will reflect known data rather than forecast uncertainty.

Is the volume reliable enough to trust the price?

At $5,263 total volume, this market reflects a small number of traders. The deep liquidity at $84,942 means price can move sharply on a single informed bet. Treat the current probability as a directional signal, not a precise consensus estimate.