Corona del Mar's Tide Pools and Grunion Runs Are Timed by the Same Two Nights Each Month

Walk down Poppy Avenue toward the Buck Gully trailhead on a weekday morning and you'll pass at least one neighbor checking a tide app before deciding whether to bring the kids down to Little Corona later. Come back after dark on the right night in August and you might find a small cluster of people standing quietly at the waterline at Big Corona, waiting for something silver to show up in the shallows. Most people in this neighborhood treat those as two separate errands: a daytime beach thing and a nighttime beach thing. They're not. Both are set by the same lunar event, and once you see the connection, the whole late-summer routine here starts to make more sense.

The grunion runs at Corona del Mar State Beach and the low tides that expose the tide pools at Little Corona are both driven by spring tides, the exaggerated highs and lows that follow the new and full moon. That's when the water pushes furthest up the sand at night, which is what triggers grunion to spawn, and it's also when the water pulls back furthest during the day, which is what opens up the rocky pools at Little Corona for viewing. Two effects, one cause. If you're only tracking one of them, you're missing the pattern that governs both.

Why the same nights do double duty

California grunion (Leuresthes tenuis) come ashore to spawn only along this coast and just south of it in Baja, and the timing isn't random. They ride the highest tides of the new and full moon cycles onto the sand at night, and Corona del Mar State Beach's own profile confirms the run happens right here, on the beach at the entrance to Newport Harbor, during spring and summer night tides. The same syzygy that produces that unusually high water at night also produces an unusually low low tide during the day, which is exactly what strips back the water at Little Corona and leaves the anemones, sea stars, crabs, and the occasional octopus exposed in the rocks at the edge of the cove.

The tide that pulls the grunion onto the sand at night is the same tide that pulls the water off the rocks at Little Corona the next morning.

This isn't a secret, exactly. It's just not how most people frame it, because the two activities get marketed separately: tide pooling as a family outing, grunion watching as a nighttime curiosity. Locally, they're the same calendar entry.

Little Corona, not Big Corona

Worth being precise here, because the two beaches at Corona del Mar State Beach serve different purposes and get confused constantly. Big Corona is the wide sandy stretch where people claim fire pits at dawn and boogie board off the jetty. Little Corona is the smaller, rockier cove tucked around the point at the mouth of Buck Gully, and it's the one with the tide pools. If you're heading down specifically to look at marine life rather than sunbathe, Little Corona is the destination, not the main beach.

The rules there are simple and worth repeating because they matter for the ecosystem: look, photograph, and touch gently, but nothing leaves the cove, and any rock you turn over to look underneath goes back exactly where it was. The same underlying idea applies to grunion. Hands only, no digging holes in the sand to trap them, and whatever you take you actually use.

What Buck Gully looks like right now

The trail starts at 872 Poppy Avenue and follows the same creek canyon that eventually carves its way out to Little Corona at the coast, though the maintained trail itself runs inland toward San Joaquin Hills Road rather than out to the sand. It's the kind of shaded canyon most residents drive past without ever noticing it's there. Round trip estimates vary a bit depending on the source, somewhere between four and five miles depending on whether you loop back through the Bobcat Trail junction, with a couple hours being the typical time investment. It's not a hard hike. The grade is gentle, there are three aluminum footbridges crossing the creek along the way, and it stays shaded enough to make a warm August morning tolerable.

Two things have changed the character of the trail in recent years that are worth knowing before you go. First, mountain bikes have been restricted to uphill-only travel on Buck Gully since October 2019, so hikers aren't dodging downhill riders coming the other way. Second, the Buck Gully Reserve has an active restoration effort underway, led by the Irvine Ranch Conservancy, to repair damage caused by years of people wandering off the marked path. The only two legal trails inside the reserve now are Buck Gully itself and the connecting Bobcat Trail. Staying on those two paths isn't just trail etiquette anymore. It's part of why the canyon still has the wildflowers and creek crossings that make it worth walking in the first place.

Dogs aren't allowed inside the reserve, which surprises some newer residents given how dog-friendly the rest of the neighborhood is. If you're bringing a leash, this isn't the trail for it.

The clock on this year's grunion season

Grunion season in 2026 runs March 1 through August 31, which means as of today there are roughly three weeks left before it closes entirely until next spring. But the season isn't one continuous window with the same rules throughout. The state splits it into a closed period, when grunion can only be observed and never touched, and an open period, when hand-catching is legal with a fishing license.

The counterintuitive part is that the closed season, April through June, is also peak spawning, when the runs are biggest and most reliable. By the time August's open season rolls around, the fish are legal to take by hand but the runs themselves have thinned out considerably from their spring peak. So the trade-off this month is real: you're in a legal window, but you're past the best show of the year, and in three weeks the grunion season closes entirely until next March.

The Saturday that ties it together

None of this requires a special trip. The Corona del Mar Certified Organic Farmers Market has run every Saturday since 1996 at Marguerite Avenue and Pacific Coast Highway, rain or shine, from 9am to 1pm, and it's a short drive from both the Poppy Avenue trailhead and Little Corona. Walk the market for produce and prepared food in the morning, hike the gully separately while the canyon is still cool, check the tide before you commit to Little Corona so you're not staring at a beach that's still underwater, and if the moon phase lines up, come back after dark to see whether anything's running at Big Corona.

That's the actual rhythm of this stretch of coast in late summer, not a list of separate errands but one tidal mechanism playing out across a single day if you time it right. The version of this neighborhood that shows up in generic guides treats the beach, the trail, and the market as three unrelated bullet points. Anyone who's actually lived here long enough to notice the pattern knows they're reading the same tide twice.

If you're already tuned into this stretch of coast and want to talk through anything else happening in the neighborhood, from trail conditions to what's opening on the harbor, David Espino knows Corona del Mar at this level of detail because he works here every day. Let's Connect.