Is My Baby Too Hot or Do They Have a Fever?

Is my baby hot or do they have a fever? Here's how to tell

You're cuddling your little one and something just feels… off. They're warm. Maybe a bit flushed. And now you're Googling at 2am wondering if you should be worried.

First — take a breath. This is one of the most common things I get asked about in my classes, and the good news is, there's a really simple place to start.

Take their temperature

The most reliable way to check a young baby's temperature is in the armpit — what we call an axillary reading. Pop a digital thermometer under their arm, hold their arm snug against their body, and wait for it to beep.

Here's what the numbers mean:

• Below 36.4°C — Could be too cold. Add a layer and recheck.
• 36.4°C–37.4°C — Normal range for babies. Happy days.
• Above 37.5°C — Borderline. Worth stripping off a layer, checking the room, and retaking in 20 minutes.
• 38°C or above — This is a fever. Time to act (more on that below).

Before you panic, ask yourself these questions

If the reading is on the higher side, just have a think:

• Have you just been breastfeeding? Skin-to-skin and feeding can warm a baby up quickly.
• Is the room really warm? Babies can't regulate their temperature the way we do.
• Are they overdressed? Newborns especially get layered up out of love — but sometimes that's all it is.

If the answer is yes to any of these, strip off a layer or two, let them cool down for 20 minutes, and take the temperature again.

When should I be worried?

This is the important bit. Call your GP, midwife, or NHS 111 if:

• Your baby is under 3 months and has a temperature of 38°C or above — always get this checked, even if they seem fine
• Your baby is 3–6 months with a temperature of 39°C or above
• The fever doesn't come down, or keeps coming back
• Your baby seems unusually drowsy, difficult to wake, or just not themselves

Call 999 immediately if your baby:

• Has a fit (febrile convulsion)
• Has a rash that doesn't fade when you press a glass against it
• Is struggling to breathe
• Seems limp or unresponsive

Trust your gut. You know your baby. If something feels wrong, get help — you're never wasting anyone's time.

Want to feel more confident in situations like this?

This is exactly the kind of thing we cover in my 2-Hour Parent First Aid course — what's normal, what's not, and what to do while you're waiting for help. No scary medical jargon, just calm and practical skills you'll actually remember at 2am.

Book your private course in South London. You'll leave feeling so much more prepared. 💛

Eva — And Chillax

Eva Levinson is a part-time Postnatal Midwifery Assistant & Infant Feeding Specialist for the NHS, a Doula UK trained postnatal doula, and an Ofsted/HSE compliant first aid instructor. She runs And Chillax in Anerley, South London.