The Prediction Markets

How many Chinook will pass Bonneville Dam by October 31?

Closes
Nov 4, 2026, in 12 days
Traded
$13K
Venues
Polymarket
Prices updated
2 min ago
Share

What the markets expect

More than 550,000 99.3%

Next is More than 575,000 at 98.7%. Only Polymarket lists this market, so there is no second price to compare.

Odds by venue

Consensus blends each venue’s last price, weighted by how much has traded there. Best Yes price is the cheapest ask across venues, and the payout is what a winning $100 stake returns before fees. Open a row for each venue’s contract name, bid and ask, and how closely their rules match.

Prices come from our regular polls of each venue, the oldest 2 min ago. Ages are as of when this page was built.

  • Polymarket
More than 550,000
99.3%
Polymarket 99.3%polled, 2 min agoBest Yes 99.6¢ on Polymarket, $100 pays $100 (1.00x)
Polymarket
Contract
More than 550,000
Last price
99.3%
As of
Polled 2 min ago
Buy Yes
99.6¢
Sell Yes
99¢
$100 on Yes pays
$100 (1.00x)
Volume
$2K
Trade this on Polymarket
More than 575,000
98.7%
Polymarket 98.7%polled, 2 min agoBest Yes 99.8¢ on Polymarket, $100 pays $100 (1.00x)
Polymarket
Contract
More than 575,000
Last price
98.7%
As of
Polled 2 min ago
Buy Yes
99.8¢
Sell Yes
97.6¢
$100 on Yes pays
$100 (1.00x)
Volume
$3K
Trade this on Polymarket
More than 585,000
18.5%
Polymarket 18.5%polled, 2 min agoBest Yes 34¢ on Polymarket, $100 pays $294 (2.94x)
Polymarket
Contract
More than 585,000
Last price
18.5%
As of
Polled 2 min ago
Buy Yes
34¢
Sell Yes
3¢
$100 on Yes pays
$294 (2.94x)
Volume
$964
Trade this on Polymarket
More than 595,000
5%
Polymarket 5%polled, 2 min agoBest Yes 7¢ on Polymarket, $100 pays $1,429 (14.3x)
Polymarket
Contract
More than 595,000
Last price
5%
As of
Polled 2 min ago
Buy Yes
7¢
Sell Yes
3¢
$100 on Yes pays
$1,429 (14.3x)
Volume
$846
Trade this on Polymarket
More than 600,000
3.3%
Polymarket 3.3%polled, 2 min agoBest Yes 6.2¢ on Polymarket, $100 pays $1,613 (16.1x)
Polymarket
Contract
More than 600,000
Last price
3.3%
As of
Polled 2 min ago
Buy Yes
6.2¢
Sell Yes
0.3¢
$100 on Yes pays
$1,613 (16.1x)
Volume
$3K
Trade this on Polymarket
More than 650,000
2.7%
Polymarket 2.7%polled, 2 min agoBest Yes 4.8¢ on Polymarket, $100 pays $2,083 (20.8x)
Polymarket
Contract
More than 650,000
Last price
2.7%
As of
Polled 2 min ago
Buy Yes
4.8¢
Sell Yes
0.5¢
$100 on Yes pays
$2,083 (20.8x)
Volume
$2K
Trade this on Polymarket
More than 625,000
0.8%
Polymarket 0.8%polled, 2 min agoBest Yes 1.5¢ on Polymarket, $100 pays $6,667 (66.7x)
Polymarket
Contract
More than 625,000
Last price
0.8%
As of
Polled 2 min ago
Buy Yes
1.5¢
Sell Yes
0.1¢
$100 on Yes pays
$6,667 (66.7x)
Volume
$1K
Trade this on Polymarket

Who resolves this market

Polymarket
Polymarket resolves via:
UMA optimistic oracle, source: cbr.washington.edu

How the odds have moved

The top 3 outcomes on both venues, with the consensus between them. Hover for exact values.

  • More than 550,000
  • More than 575,000
  • More than 585,000

Order books

Each venue’s resting orders for the selected outcome’s Yes contract, side by side. Top of book streams live; depth refreshes every 15 seconds.

Polymarket

Open on Polymarket ↗

Top of book

Connecting
Best bid
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Spread
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Best ask
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Depth · top 8 levels

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Recent trades

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What your stake buys

Enter a stake to see where it buys the most after fees, using each venue’s live order book.

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Buy

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Buys at the asks resting now (taker orders), cheapest after fees first, from order-book snapshots up to 15 seconds old. Fees: Kalshi 0.07 × price × (1 − price) per share, rounded up to the cent; Polymarket 0.05 × price × (1 − price) per share (other / general rate). Fee calculator. Estimates only, not advice.

About this market

Live prediction market odds for "How many Chinook will pass Bonneville Dam by October 31?". More than 550,000 leads at 99.3%. Next is More than 575,000 at 98.7%. $13K has traded across 7 outcomes on Polymarket. The market is expected to resolve by Nov 4, 2026.

This market will resolve to "Yes" if "Chinook" Adult Passage Annual Count at Bonneville Dam from January 1, 2026 through October 31, 2026, 11:59 PM ET, exceeds the listed value. Otherwise, this market will resolve to "No". Each market in this event will resolve independently, and any number of these markets, including all or none, may resolve to "Yes". The qualifying data is the Adult Passage Annual Count for Bonneville Dam for the date range January 1, 2026 through October 31, 2026, 11:59 PM ET. Jack Chinook will not be considered for resolution. A value exactly equal to the listed value will resolve to "No". The value read for that date range is final, and counts for dates after October 31, 2026 are disregarded. The count is used as published, without expansion, interpolation, or adjustment, and annual and year-to-date summary totals are not used. The resolution date is November 3, 2026, 11:59 PM ET, extending to November 17, 2026, 11:59 PM ET if the count through October 31, 2026 has not been published by that time. If DART has not published the count through October 31, 2026 by November 17, 2026, 11:59 PM ET, this market will resolve based on the available data. If Columbia River DART becomes unavailable and does not re-appear by November 17, 2026, 11:59 PM ET, all markets will resolve to "No". No substitute data provider will be used. Revisions published before the controlling deadline are incorporated; revisions published after the controlling deadline are disregarded. The primary resolution source for this market will be the Columbia River DART Adult Passage Annual Count for Chinook at Bonneville Dam, available here: https://www.cbr.washington.edu/dart/cs/php/rpt/adult_annual.php?outputFormat=html&proj=BON&startdate=1/1&enddate=10/31

Questions

What does the consensus price mean?

It is the price of a Yes contract that pays $1 if the outcome happens. A 14¢ price means traders put the chance near 14%. Where two venues list the same outcome, we blend their last prices, weighting the venue with more trading volume more heavily (neither counts for less than a quarter). When only one outcome can win, each venue’s prices add up to a little over 100% (its margin); the fair chance removes that margin so the outcomes add up to exactly 100%.

How is the payout worked out?

A Yes contract pays $1 if it wins, so at the best ask a $100 stake buys 100 ÷ ask contracts. At 18¢ that is about 555 contracts, paying $556 (5.56x) if Yes happens. Venue fees and price slippage on larger orders are not included.

Why do the venues show different prices?

Each venue has its own traders, fees and order book. Contracts can also settle on slightly different terms, which is why each row lists how closely the rules match.

Is a price gap an arbitrage?

Only when you can buy Yes on one venue below what someone pays for Yes on the other, after fees, and both contracts settle the same way. We show the executable bid and ask so you can check.

How fresh are these prices?

Venue prices refresh every few minutes, and the order book and live quotes stream continuously. Each venue’s card shows when we last observed it.

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