The 5-minute weekly mold check is the habit that catches problems in their first week. This is the other half of that habit — the lower-frequency rhythm that catches the problems a weekly walk-through can’t see, because they take a season’s worth of attention to develop.

The weekly check is about noticing. The seasonal check is about doing. Cleaning gutters before the leaves fall. Servicing the AC before you need it. Auditing the humidifier before the windows start weeping. Together they cover the maintenance most homes never receive — not because the owners don’t care, but because nobody ever handed them a calendar.

Here is the calendar.

Why the seasonal cadence is the easiest one to keep

There’s a reason gym memberships fail in February and seasonal chores don’t. Habits attached to a date — “service the furnace on October 15” — rely on you remembering the date. Habits attached to a season — “service the furnace when the leaves turn” — rely on the world reminding you. When the leaves are on the ground, the gutters need cleaning. When the first cold night comes, you check the windows for condensation. The cue is the weather, and the weather is hard to miss.

The other reason this rhythm works is that the jobs themselves are season-specific. You cannot service the AC condensate line in February in Minnesota; the unit is buried in snow. You should not clean the gutters in July; you’ll just be doing it again in November. Each task belongs to the season it belongs to, which means there is exactly one right time to do it, and the right time comes around every year on its own.

Pick a weekend morning per season — four mornings a year, plus the weekly five minutes — and you will have done more for your house than ninety percent of homeowners ever do.

Spring (March–May)

Spring is the survey season. The house has been through its hardest months, and you’re walking the perimeter to see what winter did.

  • Walk the exterior. Slowly, all four sides. You’re looking for ice-dam damage at the roofline, flashing that’s dropped or curled, foundation cracks that opened over winter, displaced splash blocks at the base of downspouts. Take pictures of anything new; comparing them next spring is how you’ll notice slow deterioration.
  • Clean the gutters. Even if you cleaned them in fall, the winter drops more debris and the spring rains are heavy. While you’re up there, confirm every downspout extends at least five feet from the foundation. A downspout dumping water against the wall is the single most common cause of basement moisture problems.
  • Service the AC. Have a technician check refrigerant, clean the coils, and — critically — inspect the condensate line, drain pan, and condensate pump if you have one. A clogged condensate line in August can flood the ceiling of the room below. This is one of the most common preventable water disasters in American homes, and a spring service call costs less than the drywall repair.
  • Inspect the attic from the hatch. Open it up, shine a flashlight around. Any signs of winter condensation? Matted insulation, frost stains on the underside of the roof deck, dark patches around vent penetrations? You’re not climbing in; you’re glancing for evidence.
  • Walk the crawl space. Any standing water from snowmelt or spring rains? Any new musty smell? The crawl space is where moisture problems hide; spring is when they’re easiest to see.
  • Re-caulk the silicone beads around the tub and shower. The dry indoor air of winter shrinks silicone and opens small gaps. They are cheap to redo and expensive to ignore.

Summer (June–August)

Summer is the high-humidity season indoors as well as out. The work is about keeping moisture from accumulating in the spaces it loves.

  • Run the dehumidifier. In basements and crawl spaces, set it for the target band of 30–50% RH, empty or auto-drain it, and check it monthly. Clean the filter once a season — a dirty filter cuts efficiency in half.
  • Use the range hood and bath fans deliberately. Peak indoor humidity comes from showers, cooking, and laundry. Summer is when the air can’t absorb the extra load. Run the range hood every time the stove is on; leave bath fans running fifteen minutes after every shower.
  • Inspect window AC units if you have any. They should drain cleanly to the outside, not back into the wall cavity. Foam-seal any gaps around the unit; gaps are humid-air entry points and pest highways at once.
  • Schedule the annual chimney inspection if you use a fireplace or wood stove. Do it in July, not October. By fall the good sweeps are booked weeks out and you’ll be tempted to skip a year. A poorly-drafting chimney is a combustion-gas problem and a moisture problem at the same time.
  • Check the washing-machine hoses. Pull the unit out far enough to see them. Rubber hoses should be replaced every five years; metal-braided last longer but still age. A burst washer hose is the classic catastrophic indoor flood — sixty gallons an hour, all over the laundry-room floor.

Fall (September–November)

Fall is the biggest moisture-prevention season of the year. The list is long because the stakes are highest: every job here is something that will hurt you in winter if it isn’t done now.

  • Clean the gutters again after the leaves are down. Yes, again. A blocked gutter in November is an ice dam in January.
  • Disconnect garden hoses from outdoor spigots. Install frost-free covers. A hose left attached during a freeze is a burst pipe inside the wall.
  • Service the furnace. Combustion test, heat-exchanger inspection, fresh filter. A cracked heat exchanger leaks carbon monoxide into your house; an unserviced furnace is the single most common reason for an emergency call at 2 a.m. in January.
  • Test the CO alarms. Push the button on every one. Replace batteries even if they’re still beeping. Replace any unit older than its rated lifespan — most are 5 to 10 years. CO alarms expire; the sensor degrades whether or not the battery is fresh.
  • Clean the dryer vent. Annual minimum; twice a year if you do heavy laundry. A clogged dryer vent is a fire risk first and a moisture risk second — the damp lint accumulates in the duct and becomes a small mold habitat of its own.
  • Inspect the bathroom fans. Hold a tissue to the grille while the fan is running; it should hold against the grille on its own. If it doesn’t, the fan is moving less air than it should — clogged grille, collapsed duct, or a fan that’s reached the end of its life. Vacuum the grille while you’re there.
  • Check the windows on the first cold night. Bedroom windows especially. If you see condensation pooling on the inside of the glass, your indoor humidity is higher than the windows can handle. Lower the humidity first; improve the windows over time. See the humidity guide for the full discussion.
  • Check the weatherstripping around the attic hatch. Attic hatches are notorious air-leak points, which means warm humid indoor air pouring up into a cold attic — exactly the recipe for the frost stains you’ll find next spring.

Winter (December–February)

Winter is the watch-and-wait season. The big preventive work was done in fall. The job now is monitoring, and catching the problems that only appear when it’s cold.

  • Watch for ice dams. Icicles along the gutter edge are pretty; ridges of ice damming the gutter are not. Salting and raking the roof are short-term measures. The long-term fix is air-sealing and insulating the attic floor so the roof deck stays cold and the snow melts evenly. Put it on the spring list if you see one form.
  • Audit the humidifier. Whole-house HVAC humidifiers are commonly set too high. In winter, keep indoor RH at or below 40% — ideally a little lower in the coldest weeks. Over-humidified houses in winter develop window condensation, attic moisture, and eventually mold around windows and in upper corners. If your hygrometer is reading 50% in January, the humidifier is doing too much.
  • Read the hygrometers monthly. Note them on your hygrometer log. Slow drift over the winter is information; sudden change is a signal to investigate.
  • Prevent frozen pipes during cold snaps. Open cabinets under sinks on exterior walls so room heat reaches the plumbing. Let faucets drip on the coldest nights — a moving trickle is much harder to freeze than still water in a pipe.
  • Keep the “deal with it in spring” list. Anything you see in winter that you can’t fix until the weather breaks — a piece of flashing you noticed, a section of grading that’s clearly wrong, a window seal that’s failed — write it down. The list becomes your spring punch list.

The annual jobs

A handful of jobs don’t fit any one season; they just need to happen once a year. Pick a month and stick to it.

  • Full HVAC service. Some people prefer fall; others split it into two visits, spring for the AC and fall for the furnace. Either approach works. The point is that it happens.
  • Roof inspection. A visual look from the ground every year, plus a contractor’s eye every two or three years. Binoculars are the cheapest roof-maintenance tool you can own.
  • Foundation inspection. Walk the perimeter looking at the grading, the cracks (new ones, widening ones), and how drainage actually performs during a heavy rain. Stand in the yard during the next thunderstorm with a flashlight; you’ll learn more in ten minutes than in a year of looking at it dry.
  • Whole-house plumbing walk-through. Every fixture: any drip, any slow drain, any toilet that runs. The water heater: how old? Any rust around the base? Tanks have a finite lifespan and they tend to fail catastrophically.
  • Smoke and CO alarms. Test every one. Replace any that’s past its rated lifespan.
  • Hygrometer accuracy check. Put your hygrometers in the same room for a day and compare. If three of them read 45%, 46%, 45% and the fourth reads 58%, the fourth is lying. Replace it.

Building the list into your life

Four weekend mornings a year is not a heavy lift, but it has to actually happen. A few ways to make it stick:

  • Recurring calendar reminders — one per season, set to recur annually. “Spring exterior walk” the first Saturday of April. “Fall gutter day” the first weekend of November. Adjust to your climate.
  • Anchor to weather cues, not dates. The reminder gets you in the right month; the weather tells you the right weekend. When the leaves come down, the gutter weekend has arrived.
  • Keep a one-page log per year. What you did, what you noticed, what you deferred. This becomes the building’s history — the thing you’ll wish you had when you sell the house, or when something starts going wrong and you’re trying to remember when you last serviced it. A spiral notebook in a kitchen drawer is sufficient.

The log compounds. After three years you can see patterns — the same downspout that always clogs, the same window that always sweats first, the same corner of the basement that always reads two points higher than the rest. The house starts to teach you about itself.

If you’re behind

A lot of people read a list like this and feel an immediate guilt about everything they haven’t done. Don’t try to catch up in one weekend. That’s how people burn out and abandon the whole project.

Start with the season you’re in. Do the work for this season. The next season will come around in three months, and you’ll do that one too. Within a year you will have done every job on the list at least once, and you will be ahead of where the previous owner ever was. The house does not care that you’re starting late. It only cares that you start.

What to do today

The right next step depends on where you are in the year:

  • In spring, walk the exterior. Look at the gutters and the grading. Schedule the AC service this week.
  • In summer, check the basement hygrometer and confirm the dehumidifier is doing its job. Schedule the chimney sweep before fall.
  • In fall, clean the gutters and call to schedule the furnace service. Test the CO alarms while you’re thinking about it.
  • In winter, glance at every hygrometer and check the humidifier setting. Open a few sink cabinets on the next cold night.

Whatever season it is, the smallest possible step toward the seasonal rhythm is the right step. The rhythm itself is what matters; the specific job is almost incidental.