Washington and Utah stock fish on different calendars, and the per-event data behind this site shows the gap month by month. In 2025 Washington’s plants peaked in April and Utah’s peaked a month later in May. The shape either side of that peak differs more than the peak does: Washington front-loads spring and goes almost quiet by midsummer, while Utah keeps stocking hard through summer and into a second autumn push.
The real numbers
These counts cover the 75 Washington lakes and 60 Utah lakes currently tracked here, not every water either state stocks. Counting 2025 events by month, Washington peaked in April with 202 events, then May with 127 and March with 94. Utah peaked in May with 116, then June with 95, September with 87 and October with 85.
The tails matter as much as the peaks. July and August together account for 20 of Washington’s 691 events that year. In Utah, July through October accounts for 275 of 673, more than 40 percent of the year.
Why the gap
Elevation is the most plausible driver, and the lake data on this site is consistent with it. Of the Utah lakes currently on the site that carry a recorded elevation, the median sits at 6,188 feet and twelve are above 8,000 feet. The Washington median is 459 feet, and the highest lake on the Washington list is 4,247 feet. That gap also shows up inside Utah on its own: high Utah lakes get their first plant of the year around June while low ones get theirs in April.
What this means for planning a trip
If you watch either state’s hub page for what’s fresh, expect Washington’s early-season push to land a few weeks ahead of Utah’s, and expect Utah to keep producing new plants long after Washington’s spring rush has ended. A low-elevation lake in either state can be stocked well before a high-country lake in the same state, so check a specific lake’s elevation and its own stocking history rather than assuming a statewide date applies evenly. Rainbow trout is the best species to watch this pattern in, since it is stocked heavily enough in both states to show the curve clearly.
This guide covers stocking timing only, not fishing season dates or regulations, which each agency sets separately and publishes on its own site. Check those directly before you go.