Washington · Black Diamond, WA

Green River float season

Gauge 12106700 on the Green River Gorge and Flaming Geyser State Park. The gorge-carved stretch by Flaming Geyser State Park that gives Seattle's south end its winter whitewater and its August tube hatch.

raftkayaktubing Fullest: Mar–May Leanest: Jul–Sep
Green River — typical flow through the year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 300 1.5k 3k 5k
median flow for the date middle half of years (25th–75th percentile) most years (10th–90th)

Right now at this gauge

loading CFS

Checking the live gauge…

Live reading from the USGS gauge page for Green River. Provisional data — subject to revision.

The year on this river

In a typical year at the Black Diamond gauge, the Green River runs fullest Mar–May and leanest Jul–Sep. Where today's reading falls inside that rhythm matters more than the raw number — the same flow that feels thin in spring can be the summer norm. Half of all past April days at this gauge ran above 1,120 CFS; the August median is 147 CFS.

Median of daily flows in each month across this gauge's full record — half of past days ran above these figures, half below.
Month Typical flow (CFS)
January 1,070
February 923
March 897
April 1,120
May 1,100
June 498
July 210
August 147
September 185
October 361
November 874
December 966

Record context

This gauge has measured daily flow since 1963 — 63 years of record. The largest daily average ever logged here was 10,900 CFS, in December 1978. Rivers do that sometimes; it's why the safety panel above isn't decoration.

Planning dates? The trip-window checker shows what flows have historically looked like on any week you pick for this river, or see what a CFS actually looks like.

More Washington float rivers

Common questions

When is the Green River usually at its fullest?

At the Black Diamond gauge, the fullest stretch of a typical year is Mar–May, with the single highest monthly median in April (about 1,120 CFS). The leanest months are usually Jul–Sep.

What is a typical summer flow on the Green River?

The July median at this gauge is about 210 CFS — half of past Julys ran higher, half lower. Late summer is this river's lean season, so expect readings to drift down as the season goes on.

Is the Green River safe to float right now?

No flow number can answer that, and this site never labels a river safe. What the data can tell you is how today's reading compares with 63 years of this date's history — well above typical means pushier, colder, faster water. Pair that context with a PFD, a look at the river from the bank, and a call to a local outfitter before you commit.

Which USGS gauge does this page use?

USGS gauge 12106700 (GREEN RIVER AT PURIFICATION PLANT NEAR PALMER, WA), chosen because it best represents the Green River Gorge and Flaming Geyser State Park. Daily records here reach back to 1963.

Data: USGS gauge 12106700, approved daily records 1963–2026, retrieved 2026-08-07. Live readings are provisional and subject to revision. U.S. Geological Survey data is public domain.