Tokyo Lowest Temp July 4: 21°C Leads at 46%

Tokyo’s overnight low on July 4 is one of the trickier short-range weather bets on the board right now. The market has landed on 21°C as the most likely minimum temperature, but at 46% implied probability, that is a plurality, not a consensus. Eleven outcome buckets split the remaining probability across a wide range from 16°C or below up to 26°C or higher. This is not a market pricing certainty. The market is pricing uncertainty, not science.

The contract asks: what will the lowest recorded temperature in Tokyo be on July 4, 2026? The 21°C outcome sits at $0.46 YES and $0.54 NO. The market closes on July 4 at 12:00 UTC. Total volume is $5,035, all of it traded in the last 24 hours, which tells you this contract opened recently and is moving fast.

How the 21°C Contract Works

This contract resolves YES if Tokyo’s official minimum temperature on July 4 lands exactly at 21°C. The Japan Meteorological Agency publishes daily minimum temperature data for Tokyo. Resolution follows that official reading. Every other outcome bucket resolves NO for this contract.

• YES ($0.46, 46% implied): Tokyo’s minimum temperature on July 4 is exactly 21°C.
• NO ($0.54, 54% implied): Tokyo’s minimum temperature on July 4 is any value other than 21°C, including 20°C, 22°C, 19°C, or outside the range entirely.

The NO case here is structurally broad. Tokyo’s minimum temperature missing 21°C exactly is the base case for ten other outcome contracts. Early July in Tokyo sees overnight lows typically ranging from 20°C to 25°C, depending on whether a Pacific high is pushing warm humid air over the Kanto plain or a frontal boundary is sitting offshore. A reading of 22°C or 23°C, which are both plausible given July’s usual pattern, wipes this contract out entirely.

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Momentum and Market Signals

The combined momentum signal here is mildly bearish. The 1-hour price change is down 1.5%, and the trend score sits at 36.83, which is below the midpoint of a neutral range. That softening likely reflects traders redistributing probability toward adjacent temperature buckets, particularly 22°C and 20°C, as short-range forecast models update ahead of the resolution date.

Volume is $5,035 over 24 hours, which is the entire market volume. Liquidity stands at $41,000, meaning the order book is reasonably deep relative to volume. But total volume below $1,000 per outcome bucket on average means a single large bet could reprice this contract sharply. Any shift in the Japan Meteorological Agency forecast or a weather model run showing a warmer or cooler than expected air mass over Honshu could move the 21°C contract several percentage points quickly.

• The 1-hour price decline of 1.5% signals mild redistribution away from 21°C toward adjacent buckets, likely 20°C or 22°C.
• A trend score of 36.83 places momentum below neutral, consistent with a market waiting on updated forecast model data.
• Liquidity of $41,000 against $5,035 total volume means this market can handle moderate-sized bets without major slippage.
• Volume below $1 million means new forecast data or a strong weather model signal could shift pricing sharply before July 4.
• No whale trades are on record, so pricing reflects retail-level distributed sentiment rather than a large directional bet.

Lines Analysis: Where the Temperature Is Likely to Land

Here’s what the measurements are telling us. Early July in Tokyo is the heart of the rainy season transition, when the baiu front typically lifts northward. Once the front clears, nighttime temperatures in central Tokyo tend to stay elevated because of urban heat island effects and high humidity. The Japan Meteorological Agency’s Tokyo observation point, at Otemachi, consistently records minimum temperatures in the 21°C to 24°C range during this period in recent years. That makes 21°C a credible floor estimate, but not a lock.

The data doesn’t care about the politics of this bet. What matters is whether a residual frontal cloud layer or an onshore marine flow keeps temperatures from climbing too high overnight on July 3 into July 4. A cleaner, drier airmass would push the minimum toward 23°C or 24°C and kill the 21°C contract. A lingering cloud deck or light rain would suppress overnight warming and keep the minimum closer to 20°C or 21°C. Right now the market is roughly splitting between those two scenarios.

• Japan Meteorological Agency publishes official daily minimum temperatures for Tokyo. Watch for the July 4 observation to post on July 5 JST.
• Updated 72-hour forecast model runs from the European Centre for Medium-Range Weather Forecasts and the Global Forecast System will be the primary price drivers before resolution.
• Any baiu front stalling over Honshu after July 3 would push overnight lows lower, supporting 20°C or 21°C.
• A full clearance of the front and a building Pacific high would push nighttime minimums toward 23°C or higher, moving probability away from this contract.
• Urban heat island data from central Tokyo historically keeps minimums 2°C to 3°C above suburban readings, which anchors the lower bound of realistic outcomes near 20°C.

Total volume of $5,035 reflects a thin, early-stage market. The data slightly favors the NO side at this moment, not because 21°C is wrong, but because the probability mass is spread across too many adjacent outcomes for any single bucket to clear 50%. The 21°C contract is the modal pick in a crowded field.

MODAL BUT NOT DOMINANT

The 21°C outcome leads this multi-bucket market on plurality, but the NO side holds majority odds precisely because ten other temperature readings remain in play. The Japan Meteorological Agency’s reading on July 4 will be the only fact that matters.

What the market says: A 46% implied probability means traders see 21°C as the single most likely outcome without treating it as probable. With resolution in two days and volume this thin, a fresh forecast model run showing a cooler or warmer than expected airmass over Tokyo could swing this contract by five or more percentage points in either direction.

Key unknown: The July 3 evening weather model run from the Japan Meteorological Agency or the European Centre for Medium-Range Weather Forecasts is the single most important data input before this contract closes. A forecast showing Tokyo’s overnight low landing at 22°C or higher would push probability away from the 21°C bucket immediately.

This analysis reflects market conditions as of 2026-07-02. Prediction market probabilities are volatile and shift as new data and regulatory decisions emerge, especially as the 2026-07-04 resolution date approaches. Lines.com does not accept bets or provide financial or gambling advice. All market outcomes are uncertain.