Monitor — routine vet appointment

How to take a dog or cat's temperature

Use a digital rectal thermometer with a little water-based lubricant — normal range is 38.3–39.2°C; above 39.5°C is fever, above 40°C is emergency, below 37.5°C is dangerously cold.

Dog Cat

Recognise the signs

Pet feels unusually hot or cold to touch
Panting at rest in a dog, or any open-mouth breathing in a cat
Lethargy, off food, hiding
Shivering or trembling
Pet recovering from illness needing temperature monitoring

First aid steps

Use a digital rectal thermometer — flexible-tip designs are best.
Apply a small amount of water-based lubricant (KY Jelly or similar; not Vaseline).
Have a second person hold the front of the animal calmly — distract with a treat or chin-scratch.
Lift the tail and gently insert the thermometer about 2–3cm into the rectum (less for small dogs and cats).
Hold in place; most digital thermometers beep within 30–60 seconds.
Remove, read, and clean with soap and water and disinfectant wipe before storing.
Record the reading with the time and any other signs to share with the vet.

Do NOT

Do not use ear or forehead thermometers as a primary measure — they are far less reliable than rectal in pets.
Do not use Vaseline or oily lubricants — water-based only.
Do not force a struggling animal — get help, a calmer environment, or skip if pet is too distressed.
Do not use a glass mercury thermometer — risk of breakage.
Do not insert deeper than the tip plus a small portion of the thermometer.

When to phone the vet immediately

Temperature above 40°C — emergency, see dog-heat-stroke or pet-fever
Temperature below 37°C — emergency, see pet-hypothermia
Persistent fever above 39.5°C in a pet that is otherwise unwell
Persistent low temperature with weakness or wobbliness
Inability to take a temperature in a clearly unwell pet — phone the vet anyway

Common causes

Suspected fever (lethargy, off food, panting, hot ears)
Suspected heat stroke (panting heavily, bright red gums)
Suspected hypothermia (very cold, weak)
Pre-vet-call assessment when something seems off
Monitoring during recovery from illness or surgery

What the vet will need to know

Temperature reading and time taken
How the pet was at the time (resting, after exercise, after a hot car ride)
Other signs — appetite, energy, breathing rate, gum colour
Whether the pet is on any medication that affects temperature

Aftercare

Repeat the reading after 30 minutes if the first was borderline and the pet is otherwise stable.
Record readings for the vet — a brief log helps with diagnosis.
Wash and disinfect the thermometer between uses.
Keep the thermometer with the pet first aid kit.

Prevention

Practice taking your pet's temperature on a healthy day so you and the pet are both familiar with the technique — easier under stress when it counts.
Know your pet's normal — slight individual variation exists within the normal range.
Take a Pet First Aid course for hands-on practice.

Breed-specific notes

Brachycephalic breeds normally pant more and overheat faster — a baseline temperature on a calm cool day is a useful reference.
Very small dogs and cats may be reluctant; a flexible-tip thermometer and a second person make a big difference.

Frequently asked questions

What is a normal temperature for dogs and cats?

38.3–39.2°C for both species, with some individual variation. Above 39.5°C is fever; above 40°C is heat stroke or severe fever and an emergency. Below 37.5°C is cold; below 37°C is hypothermia and an emergency. Always interpret with the rest of the picture (energy, appetite, breathing).

Can I take my pet's temperature in the ear instead?

Pet-specific ear thermometers exist but are far less reliable than rectal readings in dogs and cats. Human ear thermometers are not designed for animal ear canals and give inaccurate readings. For a meaningful number, rectal is the standard.

My dog won't let me take their temperature — what now?

Try a second person to distract with food at the head end, a calm environment, and a small amount of lubricant. If still impossible, do not force it — phone the vet, describe the other signs, and let them take the temperature at the practice. A struggle that breaks trust makes future visits harder.