Quebec City in October: 11°C / 52°F afternoons, 2°C / 36°F nights, 14 wet days — colour peaks in weeks two and three, and the last week freezes.
October hands you two trips. Environment and Climate Change Canada puts Jean Lesage at 11.3°C by day and 2.4°C at night, with 115.8mm falling across about 14 days, and the agency counts a day wet at a fifth of a millimetre. Colour peaks in the second and third weeks, and Canadian Thanksgiving lands on Monday 12 October, which fills Île d'Orléans and the road toward Charlevoix. Then the back half arrives: freezing nights, and wind off the St Lawrence onto the Dufferin Terrace with nothing in the way. A quilted jacket takes that combination. Wool absorbs the shower, stays heavy all afternoon, then passes the wind straight through the weave.
The wardrobe changes mid-month. The first half of October is a foliage trip, and the last week is a winter rehearsal you do without the parka.

Fourteen days of this month have something falling on them, and the wind on the Dufferin Terrace arrives straight off the St Lawrence, so the outer layer has two jobs at once. A quilted jacket does both: the shell sheds a shower, the quilting stops wind, and light insulation covers 11°C / 52°F without cooking you at noon. Hip length matters because Upper Town is a climb, and a cropped jacket leaves a wet band at the waist every time you take the stairs.

One knit carries the whole month if it is heavy enough. Afternoons run 11°C / 52°F and nights 2°C / 36°F, a nine-degree drop you close with wool rather than with a second coat. Cream against forest green is the Charlevoix palette rather than a city one, and a boxy chunky rib takes the flannel overshirt over the top without binding at the shoulder.

Snap this over the crew from about the 20th, when the nights start reaching freezing. Forest, grey and cream check in wool flannel is the one pattern in the capsule, and it is what Saint-Roch actually wears in October: shirt-jacket, not tailoring. Two flap chest pockets take a phone and a ferry ticket, and it slides under the quilted jacket on the coldest evening without bulking up the arm.

Dark indigo, straight, no distressing and no fading, because splash off wet cobbles reads as texture on dark denim and as a stain on anything paler. The cropped hem clears the puddle at the bottom of Côte de la Montagne instead of wicking it up. This is the walking bottom for the drier first half of the month.

Your second bottom, and the reason the capsule carries two. Denim soaked at four in the afternoon is still damp the next morning in a city with 14 wet days and short October sun, so you rotate. Wide-wale corduroy runs warmer than denim at the same weight, the pile hides a splash, and mid-brown sits between the green jacket and the brown boot rather than fighting either.

Upper Town is a stair city. Côte de la Montagne is a graded hill, the Breakneck Stairs drop to Petit-Champlain, and the Plains of Abraham stay wet grass all month, so a rubber lug sole grips all three where a smooth leather sole slides. Plain toe and smooth leather rather than suede, because suede does not survive 14 days of precipitation with no drying window between them.

The piece that does the work of a heavier coat. Wound twice under the jacket collar it closes the throat gap where the wind finds you on the Terrace, and it comes off in one motion inside a Rue Saint-Jean dining room. Oatmeal rather than a dark neutral, because the capsule is already green, indigo and brown, and the scarf is where the cream in the knit comes back.

Both hands belong on the handrail. The Breakneck Stairs and the steps up from Place Royale are steep and wet, the funicular queue runs long on Thanksgiving weekend, and a shoulder bag catches the rail on every turn. A small leather backpack sits flat under the jacket, swallows the overshirt when the afternoon warms, and carries a bottle of Île d'Orléans cider home without a paper bag.
Quilted jacket open · cream chunky-rib crew · dark indigo jeans · brown plain-toe boots · oatmeal scarf · small leather backpack. Dufferin Terrace at nine, closer to the 2°C / 36°F end of the day than the 11°C / 52°F one, then the funicular down to Petit-Champlain and Place Royale by eleven.
Jacket snapped · plaid overshirt over the crew · brown corduroy trousers · same boots · scarf doubled. A 19:00 table on Rue Saint-Jean, then the climb back up Côte de la Montagne at 2°C / 36°F.
A suggested look — forest-green quilted jacket, cream chunky ribbed sweater, dark indigo straight jeans, brown leather lug boots, oatmeal wool scarf.
Per Environment and Climate Change Canada's 1991–2020 Canadian Climate Normals for Québec/Jean Lesage International Airport, climate ID 7016294: the average daily maximum is 11.3°C / 52°F, the average minimum 2.4°C / 36°F, and the daily average 6.8°C. Precipitation averages 115.8mm, and ECCC counts a precipitation day at 0.2mm or more, which puts October at about 14 of them. That is a lower bar than the 0.25mm threshold American stations use, so the count runs higher than a US comparator would suggest. NOAA NCEI's record for the same station reproduces the temperatures within a tenth of a degree. For scale on either side: September runs 19.1°C and 8.3°C, November 3.6°C and -3.8°C, which makes October the last month here that is not winter.
The second and third weeks of October in the Québec City region. Bonjour Québec publishes a seasonal colour forecast that puts the region's peak there, and Sépaq maintains a weekly colour map through the season, which is the one to check before committing to a Charlevoix drive. Height and distance from the river move the date earlier: Parc national de la Jacques-Cartier, half an hour north in a steep valley, and the orchards of Île d'Orléans both turn ahead of the Old City. Book the first week and you get a green-to-yellow city; book the last week and the colour is mostly on the ground.
A hip-length forest-green quilted jacket, a cream chunky-rib crew knit, a green plaid wool-flannel overshirt, dark indigo straight-leg jeans, mid-brown corduroy trousers, brown plain-toe boots on a rubber lug sole, an oatmeal wool scarf and a small leather backpack. Add a wool beanie only if you are here after the 20th, when the nights start reaching freezing. Leave the wool overcoat, the suede boots and anything with a smooth sole at home. A compact umbrella goes in the backpack and mostly stays there, because the jacket does the work.
A quilted jacket, and it is not close. The month brings about 14 days with precipitation across 115.8mm at an afternoon average of 11.3°C / 52°F, and the exposed walking happens on the Dufferin Terrace and the Plains of Abraham, where the wind comes off the St Lawrence with nothing to break it. A quilted shell sheds the shower and stops the wind in the same garment. Wool does the opposite: it absorbs, it stays heavy for the rest of the day, and a single-layer overcoat passes wind straight through. Save the overcoat for November, when precipitation drops to 90.9mm and the question becomes warmth rather than weather.
Six degrees colder at both ends, and that is most of the story. ECCC gives September 19.1°C by day and 8.3°C at night against October's 11.3°C and 2.4°C, with rainfall nearly identical at 111.3mm and 115.8mm. September is a shirt-and-light-jacket month where the evening asks for a knit; October is a quilted-jacket month where the knit stays on all day and the last week reaches freezing overnight. Colour is the other difference. September is green, and October is the reason people book.
Outdoorsy French rather than urban French. Saint-Roch and Saint-Jean-Baptiste run to a quilted or waxed jacket over a heavy knit, a flannel or check overshirt as the middle layer, straight dark denim or corduroy, and a real boot with a lug sole. Simons, on Saint-Joseph since 1840, and MEC out at Sainte-Foy set that register between them. The palette follows the season: forest and loden green, cream, brown and oxblood, with a check as the only pattern. What you will not see much of is street tailoring or a dress shoe outside a restaurant, because everyone is walking a graded hill on wet stone.