What “weather price” means in weather prediction markets

How to read a weather price at a glance

In simple terms: a weather price is just a shorthand the market uses to express either a probability or an expected measurement. The key thing to know is which format you’re looking at.

Here's the basic idea:

• A Yes contract — an event contract that pays $1 if the event happens — is usually priced in dollars and therefore doubles as an implied probability. If it costs $0.30, the market is saying ~30% probability.
• A scalar contract quotes a number that represents the market’s expected value for the measurement (for example, 72.4°F). That number is in the contract’s units, not cents.
• An indexed or payout-based contract shows the expected index value or a price that maps to a payout formula (for example, an index of 4.2 on a 0–10 storm index).

Common mistake: assuming every weather price is an implied probability. That holds for simple Yes/No markets but not for scalar or custom-index markets.

Side-by-side: binary, scalar, and index contracts

Below are the three common contract formats you’ll see in weather markets, shown side by side so you can compare what a price actually encodes.

Feature	Binary (Yes/No)	Scalar (numeric)	Indexed / Payout-based
Price scale	$0.00–$1.00 (often shown as cents)	Shown in measurement units (e.g., °F, inches)	Shown as index units or a numeric price tied to payout formula
What the price encodes	Implied probability the event occurs	Market’s expected value (mean) of the measurement	Expected index value or expected payout per contract unit
Units shown	Dollars/cents (implied percent)	Degrees, mm, inches, etc.	Index points or unitless number defined in contract
Typical payout at resolution	Pays $1 if event happens, $0 otherwise	Pays an amount based on the true measurement and contract formula	Pays according to the index or payout schedule in the contract
Example contract text	"Will NYC high on 2026-07-15 exceed 90°F?"	"What will NYC high on 2026-07-15 be (°F)?"	"Atlantic Storm Index on 2026-10-01 (0–10). Payout = index* $1."
When price = probability	Yes (direct)	Not applicable	Only if contract explicitly converts index to $1 payoff for threshold events

The table above shows why reading the contract text is essential: the same-looking number can mean very different things.

Worked examples: temperature, rainfall, and storm-index prices

A clear worked example helps lock this down.

If a Yes contract costs 62¢ and pays $1 if the event happens, buying one contract costs $0.62. If the event happens, the contract pays $1, so the gain before fees is $0.38. If the event does not happen, the contract expires at $0, so the loss is $0.62.

That example was a binary market. Here are three reading examples across formats:

• Temperature (binary): "Will the high in Chicago on 2026-08-01 exceed 90°F?" Price = $0.23. Read as ~23% chance the high exceeds 90°F.

• Temperature (scalar): "High in Chicago on 2026-08-01 (°F)" Current quote = 86.7. Read as the market’s best estimate for the high: 86.7°F. This is not a probability; it’s the expected temperature.

• Rainfall (binary threshold): "Total precipitation in Seattle on 2026-11-05 ≥ 1 inch?" Price = $0.52. Read as ~52% probability of at least 1 inch.

• Storm-index (indexed payout): "Coastal Storm Index on 2026-10-01 (0–10)." Quote = 4.2. Read as the market’s expected index value of 4.2 points. Check contract for payout mapping (for example, $1 × index at settlement).

A few quick interpretation notes:

• When a scalar quote looks like "72.4", check whether the contract range is limited (e.g., 0–120°F). That tells you whether 72.4 is a raw expectation or normalized.
• When a binary price is close to $0 or $1, the market is expressing near-certainty. Near $0.5 means the outcome is genuinely disputed.

Checklist: what to check in the contract text before trusting a price

Always confirm these items in the market description. Skipping them is the most common source of misreading a weather price.

• Units: °F vs °C, inches vs mm.
• Measurement location: specific station, city center, airport, or network average.
• Measurement window: the exact time period that counts (e.g., "calendar day local time", 24-hour period ending at 00:00 UTC).
• Settlement data source: which weather station, NOAA feed, or vendor will be used to determine the official value.
• Rounding and precision: how values are rounded (to nearest 0.1, 1 degree, etc.).
• Payout formula (for scalar/index): how the final numeric measurement converts to dollars or to an index payout.
• Minimum and maximum values or caps: scalar contracts often have a stated min/max that affects interpretation.
• Time zone and date format: containment of small errors from ambiguous date strings.

If any of the above is missing or ambiguous, treat the quoted price as less reliable until the organizer clarifies.

Where each format actually fits you

• Choose binary Yes/No if you want a clean probability statement (e.g., "Will it rain above 1 inch?").
• Choose scalar if you care about the expected magnitude itself (e.g., the likely temperature for planning).
• Choose indexed/payout contracts if you need a custom payout structure tied to intensity or costs (for example, payout proportional to storm severity).

Where the distinction stops mattering: if your only goal is to know whether a threshold is likely, a binary contract is usually clearer. If you need the expected value for modeling or operational planning, the scalar or index format will be more useful.

Where to go next

• What Are Prediction Markets?
• How Do Prediction Markets Work?
• What Are Yes/No Contracts?
• How to Read Prediction Market Prices