Tokyo May 11 Low Temperature: Will It Hit Seventeen?

Tokyo’s weather markets rarely generate this kind of momentum. The 17°C outcome for the lowest temperature on May 11 has moved from 27 cents to 59 cents in a single trading session. That is not noise. Something in the near-term forecast data shifted, and traders responded fast.

The market now prices 17°C as the most likely overnight low at 58.5% implied probability. Eleven outcomes compete here, from 12°C or below all the way up to 22°C or higher. The spread is wide, which makes the conviction behind 17°C worth examining. With total volume at $8,565 and a resolution window closing at 2026-05-11 12:00:00, there is very little time left for the forecast to move.

How the Tokyo Temperature Contract Works

This contract resolves on the lowest recorded temperature in Tokyo on May 11, 2026. The resolution source is Polymarket’s market resolution process, which draws on official meteorological data. Traders pick a specific temperature band. Only one band pays out. The 17°C band is currently the market leader, but eleven alternatives remain live.

• 17°C (YES): 0.59 price, 58.5% implied probability
• 16°C: competing outcome, lower probability
• 18°C: competing outcome, meaningful tail risk
• 15°C, 14°C, 13°C, 12°C or below: cooler outcomes, lower probability given current forecasts
• 19°C, 20°C, 21°C, 22°C or higher: warmer outcomes, lower probability given current forecasts

The NO side at 0.42 reflects the 41.5% probability that the actual overnight low lands anywhere other than 17°C. Tokyo’s May overnight temperatures are historically variable. The Japan Meteorological Agency tracks daily minimum temperatures at multiple city stations, and a one-degree shift in the synoptic pattern is enough to push the outcome into the 16°C or 18°C bands. That is a real possibility, not a remote one.

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Momentum and Market Signals

The composite momentum signal here is sharp. A 14.5% one-hour move, a 26.5% twenty-four-hour move, and a trend score of 76.79 all point in the same direction. The most likely driver is an updated numerical weather prediction model run, probably the Japan Meteorological Agency’s mesoscale model or the European Centre for Medium-Range Weather Forecasts output, showing stronger convergence around the 17°C band for Tokyo’s overnight low.

Liquidity sits at $9,668 and twenty-four-hour volume reached $8,250 out of a total market volume of $8,565. Almost all trading activity happened in the last day. At this volume level, a single informed trader moving a few hundred dollars can shift the price meaningfully. The market is pricing uncertainty, not science. A thin book means the current 58.5% should be read as directional conviction from a small number of participants, not a broad consensus.

• The 1h change of +14.5% and 24h change of +26.5% combined with a 76.79 trend score signal strong recent buying pressure on the 17°C outcome, likely tied to a model forecast update showing overnight convergence near that band.
• Liquidity of $9,668 is real but thin. New weather model data or a forecast revision could move this price sharply before 2026-05-11 12:00:00.
• The 30-day price range ran from 0.27 to 0.59, meaning the market opened with low conviction and has nearly doubled its implied probability on this outcome.
• Open interest at $0 suggests positions are being actively traded rather than held, which is consistent with short-term weather market behavior this close to resolution.
• Related markets show broad scientific interest across temperature and environmental events, but no direct correlation data is available for this specific Tokyo contract.

Lines Analysis: Tokyo’s Overnight Low on May Eleven

The Japan Meteorological Agency’s forecast data for Tokyo in mid-May typically shows overnight lows in the 15°C to 19°C range. May is a transitional month. The East Asian monsoon front has not yet arrived, but maritime air masses from the Pacific are already influencing the Kanto Plain’s nighttime temperatures. A 17°C low sits squarely in the climatological center of that range, which is why the market landed here rather than at 16°C or 18°C.

The 16°C and 18°C bands are the realistic alternatives. A slightly stronger upper-level trough pushing cooler air down from northern Japan would push the low toward 16°C. A persistent southerly flow ahead of a warm front would keep the overnight temperature at 18°C or above. Neither scenario requires an unusual synoptic event. Both are within normal May forecast uncertainty for Tokyo, and that uncertainty is exactly what the 41.5% NO probability is pricing.

SIGNALS TO MONITOR:

• Japan Meteorological Agency mesoscale model updates for May 11: any forecast shift toward 16°C or 18°C would reprice this contract immediately.
• European Centre for Medium-Range Weather Forecasts ensemble output: high spread in the ensemble would widen uncertainty and push probability away from 17°C.
• JMA synoptic surface analysis showing frontal position: a cold front arriving before midnight local time would favor lower temperature bands.
• Tokyo Aerological Observatory upper-air sounding data: 850 hPa temperature trends are the clearest leading indicator for overnight surface lows in May.
• Any significant deviation in the Automated Meteorological Data Acquisition System surface observations from Tokyo stations on the evening of May 10 would be a final signal.

Here’s what the measurements are telling us: the current forecast data, as reflected in the 58.5% market price, favors a 17°C overnight low. But at $8,565 total volume, this market is not deep enough to treat that number as settled. The data leans YES. The thin book means the price is fragile to any model update before resolution at 2026-05-11 12:00:00.

LINES VERDICT

Leaning Seventeen, But the Book Is Thin

The forecast data and rapid momentum both point toward 17°C as the most likely outcome, but thin liquidity means a single new model run or forecast shift could reprice this contract sharply before resolution.

What the market says: 58.5% implied probability on 17°C, supported by a sharp single-session price move from 0.27 to 0.59. The market moved fast and late, which is typical for short-horizon weather contracts. Volatility risk is high heading into 2026-05-11 12:00:00.

Key unknown: The Japan Meteorological Agency’s next mesoscale model update is the single most important input. If that run shifts the overnight low forecast toward 16°C or 18°C, the current 58.5% probability will not hold.

Scientific Context: May Temperatures in Tokyo

Tokyo’s May overnight lows have averaged between 15°C and 18°C over the past two decades, based on Japan Meteorological Agency historical station data. The city’s urban heat island effect raises overnight minimums by roughly 1°C to 2°C compared to surrounding rural stations. May sits just before the onset of the Baiu rainy season, when persistent cloud cover and warm maritime air can keep nighttime temperatures elevated. The 17°C band aligns with the climatological median for this period, which is the clearest reason it attracted the most market volume. Before 2026-05-11 12:00:00, the only data that will materially move this contract is an updated numerical weather prediction model output showing the overnight low converging on a different temperature band.

Frequently Asked Questions

• What does 58.5% probability mean here? It means traders collectively assign a 58.5% chance that Tokyo’s official lowest temperature on May 11 lands exactly in the 17°C band. It does not mean the temperature will definitely reach 17°C.
• What does the NO contract pay out on? The NO side at 0.42 pays if the actual overnight low is anything other than 17°C. The 16°C, 18°C, and adjacent bands are the most likely alternatives given current forecast uncertainty.
• What data release would move this price most? A Japan Meteorological Agency mesoscale model update showing the overnight low converging on 16°C or 18°C would immediately reprice the 17°C band lower.
• When does this market resolve? Resolution is set for 2026-05-11 12:00:00. The overnight low will be determined by official JMA station data from the Tokyo observation network.
• Is this market liquid enough to be reliable? Total volume is $8,565 with $9,668 in liquidity. That is thin. A small number of trades can shift the price significantly, so the 58.5% figure reflects limited participation, not broad consensus.

This analysis reflects market conditions as of 2026-05-10 09:14:32. Prediction market probabilities are volatile and shift as new data and regulatory decisions emerge, especially as the 2026-05-11 12:00:00 resolution date approaches. Lines.com does not accept bets or provide financial or gambling advice. All market outcomes are uncertain.