Tokyo May 31 High Temperature: Will It Hit 27°C?

With less than twelve hours before resolution, Tokyo’s May 31 temperature market has essentially closed. The 27°C outcome trades at 98.5% probability, and the price action tells the whole story: a 67.5% move in 24 hours, nearly all of it concentrated in the final hours of May 31 itself. That kind of convergence doesn’t happen on speculation. It happens when actual temperature readings start confirming the outcome.

The market question asks: what will be the highest temperature recorded in Tokyo on May 31? The 27°C outcome sits at $0.99 YES and $0.02 NO. Resolution is set for 2026-05-31 at 12:00 UTC. Total volume reached $95,481, with $82,358 of that trading in the last 24 hours alone. The market is nearly settled.

How the 27°C Contract Works

This contract resolves YES if Tokyo’s official maximum temperature on May 31 equals 27°C exactly, as reported by the resolution source. Resolution happens at noon UTC on May 31. All other outcomes, including 26°C, 28°C, 29°C, 30°C, 31°C or higher, and every value below 26°C, resolve NO for this contract.

• YES ($0.99): Tokyo’s daily maximum on May 31 is recorded as exactly 27°C.
• NO ($0.02): Tokyo’s daily maximum lands at any other temperature, above or below 27°C.

For NO to pay, Tokyo’s temperature would need to peak at 26°C or cooler, or climb to 28°C or above. Late May in Tokyo runs warm, with average highs typically in the mid-to-upper twenties. A reading outside the 27°C target at this probability level would require either an unexpected cool front or a stronger-than-anticipated heat push. At 98.5%, the market is treating neither scenario as credible.

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Momentum and Market Signals

The momentum composite here is unusually clean. A 67.5% price move in 24 hours, zero change in the last hour, and a trend score of 64.60 all point to one driver: real-time or near-real-time temperature data filtering into trader behavior. Markets don’t move like this on forecast speculation alone. The flat 1-hour reading confirms the market has reached equilibrium. Traders who disagreed with 27°C have already moved to other outcomes or exited.

Total volume of $95,481 is modest by prediction market standards, and $104,958 in liquidity slightly exceeds volume, which is an unusual ratio. Thin volume means a single large position could still move the price, but with resolution hours away, that risk window is narrow. The 24-hour volume of $82,358 represents 86% of all trading ever done on this contract. The market woke up today and ran straight to conviction.

• The 67.5% 24-hour price move, combined with a flat 1-hour reading and trend score of 64.60, signals confirmed temperature data rather than forecast momentum.
• Total volume of $95,481 is below $1M, meaning thin liquidity could allow sharp price moves if new data contradicts the consensus, though the resolution window is extremely short.
• The 86% volume concentration in the final 24 hours reflects traders waiting for real-time confirmation before committing capital.
• Trader sentiment sits at 98.5% YES versus 1.5% NO, with no meaningful dissenting position remaining in the order book.
• The $0.02 NO price represents the residual cost of uncertainty about rounding, data source timing, or a late temperature shift before the official daily maximum is recorded.

Lines Analysis: Tokyo Temperature on May 31

Japan Meteorological Agency temperature records for Tokyo in late May consistently show daily maximums in the 24°C to 29°C range, with 27°C sitting squarely in the center of that distribution. The dramatic price move from $0.27 at market open to $0.99 by midday May 31 follows a pattern seen in short-duration weather markets: the contract drifts until actual observations land, then reprices hard and fast. That repricing has already happened here. The data, whether from JMA hourly observations or weather station feeds, has apparently confirmed 27°C as the peak or a near-certain outcome.

The genuine remaining risk for NO is narrow but real. Tokyo temperature records use specific observation stations, and the official daily maximum requires the full observational day to close. If afternoon temperatures push above 27°C before the station closes its daily record, this contract resolves differently. A 28°C afternoon spike, even brief, would hand the day to a different outcome. At 98.5%, the market is saying that spike is extremely unlikely, but it has not happened yet.

• Japan Meteorological Agency final daily maximum publication before noon UTC would immediately confirm or reprice this contract.
• Any JMA hourly reading above 27°C before the official daily close would push the NO outcome back into play.
• Regional weather system changes, including convective activity or unexpected warm air advection, could shift afternoon readings in either direction.
• The related market tracking 2026’s rank among the hottest years at 60% probability adds macro context: late May 2026 is running warm globally, which marginally supports the 27°C reading over a cooler alternative.

Total volume of $95,481 is modest, but the direction is unambiguous. The data favors YES. The remaining uncertainty lives entirely in the gap between current hourly observations and the official end-of-day maximum. That gap closes at noon UTC.

LINES VERDICT

NEAR-CERTAIN YES

The market moved from $0.27 to $0.99 in a single trading day because real temperature data confirmed the 27°C outcome. That kind of repricing reflects observation, not opinion.

What the market says: At 98.5% implied probability, the market has already priced this as resolved. The $0.02 NO price reflects residual timing risk only. With resolution hours away, that probability is unlikely to move meaningfully in either direction unless JMA data surprises before noon UTC.

Key unknown: The single event that could reprice this contract is a JMA hourly observation showing Tokyo reaching 28°C or above before the official daily maximum closes. That reading, if published before resolution, would shift capital to the 28°C outcome immediately.

Scientific Context

Tokyo’s late May climate is well-documented. The city sits at roughly 35 degrees north latitude, and May marks the transition from spring to early summer. Average daily highs in the final week of May typically land between 24°C and 28°C, placing 27°C as a historically common outcome. The related Polymarket market tracking where 2026 will rank among the hottest years on record sits at 60%, reinforcing that 2026 is running above historical baselines globally. That broader warming pattern makes 27°C or above a more probable daily maximum than 26°C or below for late May Tokyo.

Before noon UTC on May 31, the event that would move this price is a JMA station reading above 27°C. After noon UTC, the contract resolves and price movement becomes irrelevant.

What is the 98.5% probability telling me?

It means traders collectively place a 98.5% chance that Tokyo’s official maximum temperature on May 31 lands at exactly 27°C. The remaining 1.5% covers timing errors, data discrepancies, or a late temperature shift before the daily record closes.

What does it take for the NO contract to pay out?

Tokyo’s official daily maximum must land at any temperature other than 27°C, whether 26°C or below, or 28°C or above. At $0.02, NO buyers are betting on a data surprise within hours of resolution.

What data or event could move this price?

A Japan Meteorological Agency hourly observation showing Tokyo above 27°C before the daily maximum closes would immediately shift capital to the 28°C or 29°C outcome contracts, repricing this one sharply downward.

When does this market resolve?

Resolution is set for May 31, 2026 at 12:00 UTC. With the market already at 98.5%, price movement in the remaining window is minimal unless a contradicting temperature reading surfaces.

Is the volume reliable enough to trust this price?

Total volume of $95,481 is below $1M, which means thin liquidity could allow sharp moves on new data. However, the 86% volume concentration in the final 24 hours reflects fresh, informed capital, not stale positioning. The price is credible given the resolution timeline.