Tokyo May 10 Low Temperature: Which Degree Wins?

Tokyo’s overnight low on May 10 has traders genuinely split. The 15°C outcome sits at exactly 50% implied probability, with nearly identical capital on both sides. That kind of deadlock in a specific temperature market usually means the meteorological picture is ambiguous enough that no one has a clear edge. Here’s what the measurements are telling us: late spring in Tokyo produces highly variable overnight lows, and a one-degree shift in where a pressure system stalls can reprice this market completely.

The momentum composite tells a sharper story. The 15°C outcome has surged roughly 22.5% in the last hour and 25.5% over 24 hours, with a trend score of 83.14. That kind of acceleration on thin volume almost always traces back to a single catalyst: updated forecast model runs. Someone looked at the latest Japan Meteorological Agency output and made a directional call. The market followed.

How the Contract Resolves on Tokyo’s May 10 Overnight Low

This contract resolves on the lowest temperature recorded in Tokyo on May 10, 2026, with the resolution window closing at 12:00 UTC on May 10. The Japan Meteorological Agency operates the official observation network for Tokyo. Whichever whole-degree Celsius value matches the official JMA low for that date wins the contract. The 15°C outcome is currently the lead position, but eleven other outcomes remain live, including 16°C, 14°C, 13°C, and 17°C.

• 15°C (Primary Outcome): Price 0.50, implied probability 50%.
• 16°C: Active, probability below 50%.
• 14°C: Active, probability below 50%.
• 13°C: Active, probability below 50%.
• 17°C: Active, probability below 50%.
• 12°C and below: Tail outcomes, very low probability given seasonal baseline.
• 18°C through 21°C or higher: Tail outcomes on the warm side.

The contract misses 15°C when the JMA official low lands on any other integer. Tokyo’s May 10 overnight lows over the past decade have clustered between 13°C and 18°C, so outcomes outside that band carry genuine but limited weight. A warmer-than-expected synoptic pattern keeps 16°C and 17°C competitive. A cold front passage keeps 13°C and 14°C in the conversation. The data doesn’t care about the politics of which traders are positioned where.

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Momentum, Thin Volume, and What the Market Is Actually Pricing

The combined momentum signal, that 22.5% hourly gain, 25.5% daily gain, and 83.14 trend score, points to a rapid repricing event that almost certainly followed an updated JMA forecast or a global model ensemble shift. In short-horizon temperature markets, sharp price moves on low volume typically signal a trader acting on fresh forecast data rather than broad market consensus.

Total volume sits at $5,689, with $4,828 of that traded in the last 24 hours. Order book depth is $13,171. These are thin numbers. Volume well below $1 million means a single medium-sized trade can move this contract sharply. The current 50% price reflects a genuinely uncertain forecast, not deep liquidity and broad agreement. The market is pricing uncertainty, not science.

• 1h change +22.5%: Signals a fresh catalyst, likely an updated forecast model run from JMA or ECMWF, that pushed capital toward 15°C in a single session.
• 24h change +25.5%: Confirms directional conviction has built over the full trading day, not just a brief spike.
• Trend score 83.14: High relative to this contract’s history, suggesting the move is not noise.
• Volume $5,689 total: Thin enough that one trade of $500 to $1,000 can shift the implied probability by several percentage points.
• Liquidity $13,171: Order book depth is present but not deep. Large positions would move the price significantly.

Lines Analysis: Tokyo Temperature Forecasting at the One-Degree Level

The Japan Meteorological Agency’s operational models have strong skill at 24-hour temperature forecasts for Tokyo. The city’s urban heat island effect tends to push overnight lows slightly warmer than surrounding suburban areas, and the official JMA station captures that consistently. If current model runs are centering on 15°C, the recent momentum makes sense. May 10 sits in a transitional period where Pacific high pressure and continental air masses compete, producing exactly the kind of borderline overnight lows that land right between forecast bins.

The real risk to the 15°C outcome comes from model uncertainty at the margins. ECMWF and JMA ensemble spreads for late-spring Tokyo nights often span two to three degrees at the one-degree level. A surface low tracking slightly closer to the Kanto Plain than forecast could push the official low to 13°C or 14°C. A persistent southerly flow keeping warm Pacific air in place could lift the low to 16°C or 17°C. Neither scenario is far-fetched given the synoptic pattern typical for this date.

• JMA 24-hour forecast update: Any revision shifting the point forecast above 15.5°C or below 14.5°C would directly reprice competing outcomes and likely drain capital from the 15°C position.
• ECMWF ensemble spread: A tightening ensemble around 15°C confirms current pricing. A widening spread reopens 14°C and 16°C.
• Surface low track: A front passing Tokyo before 06:00 JST on May 10 is the clearest pathway to a sub-14°C outcome.
• Urban heat island persistence: Clear skies and calm winds amplify radiative cooling, potentially pushing the official low below model guidance.
• Resolution timing: The contract closes at 12:00 UTC, which is 21:00 JST on May 10. The official daily low will be fully recorded well before that cutoff.

Total volume of $5,689 and open interest of zero suggest this market has attracted speculative positioning but not sustained institutional attention. The data currently favors 15°C, but the margin is razor thin. At 50%, this is a genuine coin flip dressed in meteorological clothing.

LINES VERDICT

Dead Heat Pending Final Forecast

The 15°C outcome has momentum and fresh capital behind it, but a 50% probability on a thin-volume market means the meteorological picture has not resolved enough for traders to commit heavily in either direction.

What the market says: The 15°C outcome carries a 50% implied probability, a literal coin flip, and the contract resolves at 12:00 UTC on May 10, 2026. Thin volume means any late forecast update could move the price sharply before the window closes.

Key unknown: The Japan Meteorological Agency’s next operational forecast run, expected in the hours before resolution, is the single data point that would most directly reprice this contract. A point forecast shift of even one degree could collapse or significantly extend the current 15°C lead.

Scientific Context: Tokyo Spring Temperature Baselines

Tokyo’s May overnight lows have a well-documented climatological range. JMA historical records show May 10 lows averaging around 14°C to 16°C over the past 30 years, with year-to-year variability driven primarily by the timing of the East Asian rainy season onset and Pacific high pressure positioning. The 2024 and 2025 spring seasons both ran warmer than the 30-year mean, consistent with a broader regional warming trend. That context gives a slight climatological edge to outcomes in the 15°C to 17°C range over colder bins. Before the 12:00 UTC resolution on May 10, any synoptic shift captured in the 00Z or 06Z JMA model runs would be the most direct price mover for this contract.

Frequently Asked Questions

• What does 50% probability mean here? The 15°C outcome at 50% means traders currently assign equal probability to that exact temperature and to every other possible outcome combined. It reflects genuine meteorological uncertainty, not a weak market signal.
• How does the contract pay if the temperature is 14.8°C? The Japan Meteorological Agency reports official lows to the nearest tenth of a degree, and the contract resolves on the whole-degree integer matching the JMA official low. A reading of 14.8°C would resolve as a 15°C outcome under standard rounding.
• What data release would move the price most? A JMA operational forecast update shifting the Tokyo overnight low point estimate by one degree in either direction would be the most direct catalyst for a significant price move before the May 10 resolution.
• When does this contract resolve? The resolution window closes at 12:00 UTC on May 10, 2026, which is 21:00 JST. The JMA official daily low will be recorded and available well before that cutoff.
• Is $5,689 in total volume enough to trust this price? Volume below $1 million means the current 50% price can shift sharply on a single trade or a new forecast update. Treat the implied probability as directional guidance, not a deep-market consensus signal.