Pacific Grove's Monarchs Spent Last Winter on One Edge of the Grove

Have you walked into the Monarch Grove Sanctuary on Ridge Road on a December morning, looked up, seen nothing, and decided this year must be a bust? Last season, on most of those mornings, the butterflies were there. They were roosting on a band of eucalyptus along the grove's southern boundary, where the trail and the eye don't naturally go.

That pattern comes from the City of Pacific Grove's own record. Stuart B. Weiss of Creekside Science, who has worked at the sanctuary since 1997, writes an annual assessment for the city, and the 2026 edition lays out where the monarchs sat, week by week, through the 2025–26 season. With a new season starting, it works as a field guide for anyone who lives a few blocks away.

The South Edge Did Nearly All the Work

After arriving in early October 2025, the monarchs clustered in the sunny areas on the sanctuary's South and Southwest edges. They stayed there all season. Across every observation from October through early February, 94% were on eucalyptus, 5% on Monterey pine, and 2% on Monterey cypress. Only a few made it into the South Interior just north of the main trail, and those were on pines.

That goes against what longtime visitors may remember. In 2023–24, the butterflies started on eucalyptus, moved mostly to pines by mid-November, went into the interior in early January, and ended the season along the Driveway on cypress. In 2022–23, a run of strong storms pushed them all the way into the North Interior.

Weiss explains the difference with wind, and he is clear that tree species has little to do with it. The grove's sheltered interior is mostly pine and cypress, so in stormy years the monarchs end up on those trees because that is where the calm air is. In mild years they have no reason to leave the sunny edge, and the sunny edge is eucalyptus. The 2025–26 season was mild. Monterey Airport recorded no sustained winds over 20 mph all fall, and only one stretch, around January 10, brought lows below 40°F. The 2024–25 season followed the same South Edge pattern.

The report also notes that monarchs have often clustered just outside the sanctuary to the south, on a single isolated Monterey pine. So the southern boundary deserves a slow walk, including the trees just past it.

A Small Population Is Easy to Miss

Location matters more now because the numbers are so small. During the 2025 mid-season count, the Xerces Society tallied about 12,260 monarchs at 249 sites across California, the third-lowest statewide total in the count's history. Pacific Grove's sanctuary accounted for 188 of them.

Against the grove's history, that number looks even smaller. Since 1999, the sanctuary has averaged about 7% of California's mid-season count and usually ranks among the state's top 10 sites. Last season it held 1.5% and ranked 16th. Most of Monterey County's monarchs that year were at a private site near Big Sur. Weiss also writes that Pacific Grove's numbers mostly rise and fall with the statewide population. A thin year here mostly reflects the whole western population. Nothing in the report points to a problem with the grove itself.

With a couple hundred butterflies spread across a full canopy, a group of five or ten roosting in the wrong spot can disappear from view. Weiss makes this point directly. Counts happen in the morning, when small groups tucked into the canopy are hard to find. In low-number years, he writes, it is especially important to watch in the afternoon, as the monarchs pick their roosts for the night.

What One Windy Night Did to the Count

Last winter's count shows how much a single weather event can change what you see.

The drop after Christmas wasn't a departure. The report reads it as monarchs scattering through the grove as individuals and then regrouping, which is why the count came back within days. If you walk in the morning after a blustery night and the eucalyptus looks bare, the butterflies are probably still nearby and spread out. Going back a few calm days later is the better test.

The end of the season follows the weather too. Warm temperatures and longer days break the monarchs' winter dormancy. Last season, late January brought seven days above 70°F, and the butterflies left during a stretch of high-70s weather in the first week of February. In cooler years they have stayed into March.

Matching the Visit to the Hour

The Pacific Grove Museum of Natural History, whose volunteers run the weekly counts, splits viewing into two windows, and they fit Weiss's findings well.

• Before 11 a.m., or on overcast days below 55°F, monarchs hang in clusters. They look like small pinecones or dead brown leaves, so scan the eucalyptus along the South and Southwest edges for anything that seems out of place.
• After 11 a.m., or on sunny days above 55°F, they fly. They are easiest to find around the nectar beds at the south end of the trail.
• Late afternoon is when they settle into their night roosts. In a year like this one, that is often the best time to see where the small groups actually are.
• Between 11 a.m. and 3 p.m., Monarch Docents are usually on site from October through February, weather permitting. The Museum notes that monarchs don't cluster on the same tree every day, and the docents can point out which trees they're using that day.

The sanctuary at 250 Ridge Road is open daily from sunrise to sunset. It closes only when high winds make a visit unsafe. Dogs and other pets aren't allowed inside, food and smoking are prohibited, and visitors are asked to stay on the paths. The Museum notes that the Pacific Grove Police Department enforces these rules with fines of up to $1,000. Leave the dog at home or take it along the shoreline instead.

Where This Season Stands

On October 16, 2026, the Museum reported fewer than a dozen monarchs at the sanctuary, mostly flying around the nectar beds in the lower part of the grove in the afternoon. It expects the population to peak around the end of November. Weekly counts will begin once the butterflies settle, and the Museum suggests checking its page or calling before a visit. Last year followed a similar timeline, with small numbers in mid-October and a count of 188 by mid-November.

The best family date on the calendar is the Saturday after Thanksgiving. The Museum's Science Saturday: Monarch Magic! runs November 28, 2026, from 10 a.m. to 3 p.m. Admission is free, and the day covers monarchs, their ecosystems, and habitat conservation. That falls right in the expected peak window, so you can stop at the Museum and then walk the South Edge in the afternoon.

What the City Plans for That Edge

The same sunny edge the monarchs depend on also collects the grove's fire risk. The cover of Weiss's report shows eucalyptus leaves, branches, and peeling bark piled along the South and East edges, and another photo shows a trunk scorched in a small fire on March 31, 2024.

For 2026, the report recommends clearing and redistributing that debris along the South Edge in September. It calls for leaving some material on the ground, with fuel breaks several feet wide, so a monarch that falls can climb back up. The other recommendations include:

• removing hazard trees and branches as they're found
• pausing new tree planting, except for a double row of cypress along the hotel boundary in the northeast corner
• thinning the overly dense planted cypress northeast of the nectar beds
• caging the oaks along the west boundary to protect them from deer
• reworking the nectar beds and the irrigation schedule

A similar recommendation in the previous year's report, to rearrange the forest-floor debris, was not carried out.

Environmental Program Manager George Fuerst presented the sanctuary's annual report to the Beautification and Natural Resources Commission at its August 18, 2026 meeting. At that meeting, the South Edge cleanup and hazard-tree removal were described as plans for this year. The nectar-bed and irrigation work was described as ongoing. If you walk the South Edge this fall, the ground under the eucalyptus will show how much of that work got done.

A few blocks away, George Washington Park has its own track. On August 5, according to the meeting minutes, the City Council voted 7–0 to let staff begin work under the draft George Washington Park Forest Management Plan while revisions continued. The October 21 Council agenda included an update on the park work completed in September and the final draft of the plan. Don't expect butterflies there, though. At the same August commission meeting, city staff said that monarch counts at George Washington Park have been zero or one every year since 2011, apart from 61 counted in 2011 itself. For now, the place to look in Pacific Grove is the eucalyptus along the sanctuary's South Edge, ideally on a calm afternoon.

At Dave Lucas, I see the sanctuary as one of the small seasonal rhythms that make Pacific Grove feel like home. If you'd like to talk about life in this town, or what owning a home near Ridge Road looks like through a full monarch season, Let's Connect.