November changes the room, not the cat. Heating drops indoor humidity by 10 to 20 points in a week, a space heater puts a 90 C surface within tail reach, and a skin case that looked settled in September gets a follow-up date nobody wrote down. Three numbers decide the month: 18 to 22 C for room temperature, 40 percent relative humidity as the floor, and 1 m of clearance around any heater.
Heater safety is a distance problem
A ceramic or fan heater's grille reaches 70 to 90 C within 10 minutes of switching on, and the housing of an oil-filled radiator sits at 60 to 75 C for hours. A cat's coat hides the burn for 2 to 3 days: the first sign is usually a scab on the tail tip, a crusted pad edge, or a patch of singed fur along the flank where the cat slept too close. Keep 1 m of clear space in front, 30 cm at the sides, and never park a cat bed within 1.5 m of the grille.
Three hardware points are worth more than any warning label. A tip-over switch that cuts power within 2 seconds, a cord routed behind furniture rather than across the floor, and a unit with no exposed coil. Unvented gas heaters add a second risk: carbon monoxide. A cat that starts hiding, drooling or walking unsteadily in a heated room should be carried outside to fresh air and driven to a clinic, not fanned in place. Test smoke and CO alarms once in November; the button test takes 10 seconds and the batteries cost less than 5 USD.
The humidity floor is 40 percent
Below 40 percent relative humidity, the nasal mucosa dries, the coat loses gloss, and dandruff appears along the spine within 7 to 10 days. Below 30 percent, a cat with herpesvirus or calicivirus tends to start sneezing again, and old skin cases itch more. Aim for 40 to 60 percent, and measure it 1 m above the floor, away from the heater and the window, with a 15 to 30 USD hygrometer rather than a guess.
A 20 square meter room typically needs 2 to 3 L of water evaporated per day to hold 45 percent at 22 C. Refill the tank daily and clean it every 3 days; a humidifier left 7 days grows biofilm and sprays it into the air, which is worse than dry air for a cat with asthma. Ultrasonic mist is fine at 45 to 55 percent but leaves white dust on surfaces if you use tap water, so use filtered water or an evaporative wick unit. Do not chase 60 percent and above: at 65 percent, condensation on windows starts, and mold in wall cavities becomes the next problem.
The 6-week recheck nobody schedules
Skin cases have their own clock. A dermatophyte culture needs 21 days to turn positive or be called negative, eosinophilic plaques are usually rechecked at 4 to 6 weeks, and a food-elimination trial runs 8 weeks before any conclusion. November is the right month to book the recheck for anything that started in September, because dry heated air makes every one of these look worse at week 6 than at week 2.
Photograph the lesion on the same day each week with a coin or a ruler in frame. A patch that shrinks from 3 cm to 1.5 cm in 4 weeks is winning; one that is unchanged at 4 weeks needs a different plan, not a stronger shampoo. Note the itch score too: a cat that grooms the flank for more than 5 minutes at a time, 3 or more times a day, is above the threshold where waiting another month costs fur.
November numbers
| Item | Target | Act when |
|---|---|---|
| Room temperature | 18-22 C | below 16 C at night |
| Relative humidity | 40-60 percent | below 35 percent for 3 days |
| Heater clearance | 1 m front, 30 cm sides | cat bed within 1.5 m |
| Grille surface | under 60 C touchable | 70 C or above |
| Humidifier tank | refill daily, clean every 3 days | film visible at 5 days |
| Lesion photo | 1 per week, same light | no change at 4 weeks |
Pads, salt and the walk to the door
De-icing salt is the winter version of a hot pavement burn. Granules sit between the toes, the cat licks them off, and the result is 1 to 2 days of drooling and loose stool, or a chemical burn on the pad edge. Wipe paws with a damp cloth at the door, keep a mat inside and outside, and check the 2 pads that carry most weight — the central and metatarsal pads — for cracks wider than 1 mm. A paw balm applied 2 to 3 times a week in November prevents most winter cracking, but never on an open crack.
Indoor cats still meet salt on balconies, in stairwells and on shared entrance floors. Rinse the balcony floor with plain water once a week, and keep the litter box away from the door where boots land: a cat that steps in salt and then in the box carries the grit into a place it licks.
What a November flare costs
A 6-week recheck with a culture typically runs 60 to 150 USD; a flare that needs 4 to 8 weeks of treatment plus a recheck costs 2 to 4 times that, and a humidifier plus hygrometer is 40 to 90 USD once. The full breakdown by month sits in the /tools/cost/ calculator. For the dry-air side of the problem, the /seasonal/winter-dry-heat-skin/ guide covers coat and bathing frequency, and the salt route is mapped in /seasonal/seasonal-winter-paw-salt/.
The November checklist
- Set the thermostat to 18 to 22 C and confirm the bedroom does not fall below 16 C at 3 a.m.
- Place a hygrometer 1 m above the floor and log humidity for 7 days.
- Clear 1 m around every heater and move beds at least 1.5 m from the grille.
- Refill the humidifier daily, clean it every 3 days, and use filtered water.
- Photograph any skin lesion weekly and book the 6-week recheck in the same call.
If humidity holds above 35 percent, the coat is clean at the spine, and the lesion is smaller at 3 weeks, November did its job. If the cat sneezes 3 days in a row, or a pad crack bleeds, stop adjusting the room and book an appointment: dry air explains discomfort, not a fever of 39.8 C or a limp that gets worse over 48 hours.
Terms mentioned in this article
Frequently asked
How far should a heater be from where the cat sleeps?
Keep 1 m of clear space in front of the grille and 1.5 m between the heater and any cat bed. A ceramic heater grille reaches 70 to 90 C within 10 minutes, and a cat's coat hides a burn for 2 to 3 days, so the first sign is often a scab on the tail tip rather than a visible wound.
What indoor humidity is safe for a cat in winter?
Hold 40 to 60 percent, measured 1 m above the floor and away from the heater. Under 40 percent the nasal mucosa dries and dandruff shows along the spine within 7 to 10 days; under 30 percent cats with herpesvirus start sneezing again. A 20 square meter room usually needs 2 to 3 L evaporated per day.
When should a skin case be rechecked?
Plan on 4 to 6 weeks for eosinophilic plaques and 8 weeks for a food elimination trial, with a dermatophyte culture read at 21 days. Book it in November for anything that started in September, because heated dry air makes most lesions look worse at week 6 than they did at week 2.