The foliage calendar says Boston peaks in the third week of October, and the calendar is right about the average. It is wrong about the city's best trees. Boston plants for variety, not uniformity, and a park full of species from three continents does not turn all at once. The result is a second foliage season that runs into November, after the leaf-peeping traffic has gone back to New Hampshire and the hotel rates have come down.

Four places hold color the longest. All of them are free, all of them are reachable on the T, and all of them reward a weekday visit.

Mount Auburn Cemetery, Cambridge

Founded in 1831 as the country's first garden cemetery, Mount Auburn was designed to be walked through, and it still is. More than 5,000 trees across roughly 630 species mean something is turning from late September into late November. The paths are hilly and well signed, and the Welcome Center is the place to start.

The rules here are the rules of a working cemetery, and they are worth honoring. Keep voices low, give funerals a wide berth, and stay on the paths. Washington Tower, built between 1852 and 1854, closes for the cold months and reopens April 1, so the skyline view is a spring and summer prize.

Hours shift several times a year to follow sunset, and they shorten after the clocks change on November 1. Check before going. The 71 and 73 buses from Harvard station stop directly across Mount Auburn Street, about eight minutes out, or walk the 1.4 miles along Brattle Street.

The Arnold Arboretum, Jamaica Plain

The Arboretum is Harvard's 281-acre living collection, founded in 1872 as the oldest public arboretum in North America and laid out with Frederick Law Olmsted as one link of the Emerald Necklace. It holds around 15,000 accessioned plants, with a special focus on eastern North America and eastern Asia. So many species growing side by side means a single walk passes trees at every stage, and that mix is what stretches the season.

The landscape is open daily from sunrise to sunset and admission is always free. The Hunnewell Visitor Center at the Arborway Gate is open 10 AM to 4 PM. Free guided walks typically run into mid-November. The Orange Line's Forest Hills station is a short walk from the Arboretum's southern edge, and free parking runs along the Arborway, Flora Way and Walter Street.

The Arboretum sits on the line between Jamaica Plain and Roslindale, and either neighborhood makes a good second half of the day.

Jamaica Pond

North of the Arboretum on the same Olmsted chain, Jamaica Pond is the largest freshwater body in Boston: 70 acres, formed by a glacier, and ringed by a 1.5-mile path. The loop takes about half an hour at a stroll. Late-afternoon light across the water in early November is the reason to time it.

The Emerald Necklace as a whole runs about 1,100 acres across nine parks, and walking from the Arboretum to the pond and on through Olmsted Park is a manageable afternoon.

The Esplanade and the Public Garden

The Charles River Esplanade holds color through November, and the Public Garden's specimen trees, planted in tight groupings since the garden opened in 1837, turn on staggered schedules. A loop from the Public Garden across the Arthur Fiedler footbridge and west along the river covers both, and it starts within a few blocks of Back Bay and Beacon Hill.

This is the route for a short day or a cold one. Everything is flat, and a warm room is never more than ten minutes away.

When to go

• Last week of October: the Arboretum and Mount Auburn are near their best, with the crowds a fraction of the peak-weekend crush.
• First week of November: Jamaica Pond and the Esplanade, plus a second Arboretum walk for whatever the first one missed.
• Mid-November: Mount Auburn's late trees and the Public Garden. Colors are subdued by now, but the light is low and gold for most of the afternoon.

The clocks fall back on Sunday, November 1, and sunset arrives before 4:30 PM by the middle of the month. Start walks by 1 PM.

What to bring

Layers, because a riverside wind in November is a different climate from a sheltered Arboretum hollow. Shoes with grip for wet leaves. A charged phone for the Arboretum's free Expeditions app, which offers self-guided routes through the collection.

The rules, plainly

Every place on this list is a public space, and Massachusetts state law prohibits cannabis consumption in public spaces. That includes the Arboretum, the cemetery, the Emerald Necklace parks, the Esplanade and the paths between them. Mount Auburn and the Arboretum also have their own visitor rules, and a cemetery in particular is not a place to test anyone's patience.

What it means for your foliage day

• Adults 21+ only for any purchase, with valid photo ID
• Buy from a licensed retailer and verify licensed status via the Massachusetts Cannabis Control Commission at masscannabiscontrol.com
• Keep purchases sealed and out of sight while walking; consumption belongs in a private residence where it is permitted
• Start low, go slow with edibles, and never plan a walk around one
• Never drive after consuming; the T reaches every stop on this list

Licensed stores in the city are listed in the dispensary directory, and the rest of Boston's fall calendar is on the events hub.