Why this list is ordered by deadline
Most fall checklists are organised by area — outside, inside, HVAC, yard. That is a fine way to write a list and a bad way to use one, because it hides the only thing that actually matters in autumn: some of this stops being possible, and it stops in a predictable order.
Contractors go first. Furnace technicians, chimney sweeps and septic pumpers are all booked solid within days of the first cold night. Everything on this list that needs someone else to show up belongs six weeks out, not in October.
Then water. Anything holding water outside splits when it freezes, and the split is usually in a pipe you cannot see. There is no partial credit here — the hose either came off before the freeze or it did not.
Then comfort. Caulk will not cure below about 40°F. Nobody reseals a deck in November. Work that is merely unpleasant in October is genuinely impossible in December.
Then the leaves, which have their own schedule and do not care about yours.
Enter your local first-freeze date at the top and the first two deadlines get real dates on them.
The freeze sequence, in detail
This is the part people get half right, so it is worth writing out.
1. Disconnect the hose ← the one that matters most
2. Close the interior shutoff valve
3. Open the outdoor spigot and LEAVE IT OPEN all winter
4. Drain anything else outdoors: irrigation, rain barrels, pool
Steps 2 and 3 are a pair. Closing the valve without opening the tap leaves a sealed section of pipe with water in it, which is exactly the condition that bursts. Opening the tap without closing the valve does nothing at all. Frost-free sillcocks are more forgiving, but only if the hose is off — the hose is what defeats the frost-free design, because it prevents the tap from draining back.
A burst supply pipe inside a wall releases water at household pressure, continuously, until someone shuts off the main. It is the most expensive failure on this entire site and it is prevented by unscrewing a hose.
What your first-frost date is, and where to get it
The date the list works from is the first hard freeze — around 28°F — rather than the first light frost. That is the temperature at which standing water in an outdoor pipe becomes a problem.
It varies enormously. Northern Minnesota sees it in late September; the Gulf coast may not see it at all. Your county extension service publishes local first-frost dates, and they are more useful than a national map because elevation and proximity to water shift the date by weeks over short distances.
If you would rather not look it up, err early. Nothing on this list is harmed by being done a month too soon.
Two things worth doing that are not really maintenance
Look at the roof now, from the ground. Not because autumn damages roofs, but because a roofer will still come out in October. In February they will put a tarp on it and book you for spring, and you will live under the tarp.
Find the drafts on the first cold windy day. This is the only time of year they are easy to locate — you need the temperature difference to feel them. Walk the exterior walls with a lit incense stick and watch where the smoke moves: outlets, the attic hatch, where the floor meets the wall, around window trim. Air sealing costs almost nothing and beats adding insulation on top of leaks, which is the usual instinct and the wrong one.
What the list deliberately does not include
Getting on the roof. Every roof task here is done from the ground with binoculars, or by someone with staging. October roofs are wet in the morning, and falls are the leading cause of death in residential construction.
Anything gas-fitted. The furnace service is on the list as a phone call. Combustion appliances are the category where confidence is more dangerous than neglect.
Winterising an unoccupied house. Draining a whole plumbing system for a house that will sit empty and unheated is a different and much longer procedure than anything here. If that is what you are doing, this is not the list for it.
Nothing here is urgent on the day you print it. The point of the deadlines is that they let you do the work at a comfortable pace instead of doing it badly on the evening of the first hard freeze forecast.