Nabokov's routine wasn't a strict clock. It was a set of habits he kept for decades: cards, pencil, a lectern, and a mind that did much of the drafting while his hands were nowhere near paper.

The Direct Answer
He wrote in the morning, on index cards in pencil, standing at a lectern.
A flexible schedule built around forenoon writing and a lot of composing in his head, per his 1967 Paris Review interview.

Mornings on His Feet

The core of Nabokov's day was the forenoon, the late-morning stretch when he felt sharpest. He'd wake, wash, eat, and then stand at his lectern to write on index cards in pencil. He called his schedule flexible, which for him meant the hours could move but the tools and the method stayed fixed. He cared far more about the cards and the pencils than about hitting a particular start time, and he said as much.

My schedule is flexible, but I am rather particular about my instruments: lined Bristol cards and well sharpened, not too hard, pencils capped with erasers.

Vladimir Nabokov, Paris Review, 'The Art of Fiction No. 40' (1967)

Writing on cards meant he could work in short bursts and out of order, drafting whatever scene was ready that morning. Progress showed up as a growing stack rather than a rising page count. When a batch was done, Véra typed it, read it, and told him what she thought, and that loop repeated until the book was finished. He kept this shape for decades, through Berlin, Cornell, and Montreux, adapting the surroundings but not the essentials. A routine that fits in a shirt pocket is easy to carry through an unsettled life, and his was unsettled for a long time before Switzerland.

The morning had a rhythm even when the clock didn't. He woke on the earlier side, spent a while coming to before anything productive, then washed, ate a light breakfast, and got to the lectern. Once he was standing and writing, the forenoon belonged to the book. Interruptions were kept to a minimum, and the household ran so that his best hours stayed clear.

The Walking, the Afternoon, and the Slow Pace

A lot of Nabokov's writing happened away from the desk. He composed sentences in his head on long walks through the countryside near Montreux, coming back with lines already shaped and only needing to be caught on a card. As the day went on he moved from the lectern to an armchair and then to a couch, following his own fatigue instead of a timetable. He worked at a deliberate pace, revising heavily, rubbing out and rewriting on the same card, and he never treated speed as a virtue. He often reworked a single card over successive mornings, so one passage might carry days of quiet labor before Véra ever typed it.

From the outside the routine could look almost idle. There was no visible race, no daily word target announced to anyone, no dramatic all-nighters. There was a man standing at a lectern in the late morning, filling small cards in pencil, then walking, then filling a few more. The output arrived over years, in books that were built rather than poured out, and the unhurried shape of the days is exactly what made that kind of construction possible.

The routine was steady rather than punishing. Véra ran interference on the rest of life, typing manuscripts, driving the car, answering letters, and reading every draft, which freed him to spend his best hours on the page and his walks on the sentences. She even pulled the burning pages of Lolita out of the incinerator when he lost his nerve and tried to destroy it. That division of labor was as much a part of his routine as the lectern itself, and it stayed in place from Berlin to Cornell to their long years in the hotel.

See the full Vladimir Nabokov writing routine.

What You Can Steal