Why then
Keep mowing as long as the grass keeps growing — usually until a couple of weeks after the first frost. Take the final cut slightly shorter than summer height (never scalped): shorter winter turf mats less under snow and resists snow mold. Leaves must be mulched or removed before snow regardless.
Frequently asked questions
When should I stop mowing for the year in New Hampshire?
Across New Hampshire's featured cities the window runs Sep 26 – Oct 25. Your own town can sit at either end of that range — use the city table on this page or the ZIP lookup for your exact dates.
Why do the dates vary within New Hampshire?
Because climate does. The dates here are calculated separately for each city from its own NOAA 1991–2020 frost records, and elevation, latitude, and terrain spread them across New Hampshire — the same task can be a week or two apart between towns. That local spread is exactly what generic national advice misses.
What if I miss the window?
Better to skip than to force it. Doing this job in the wrong season stresses the lawn more than not doing it at all — set a reminder for the next window.