how accurate are underarm thermometers?

[gunting]

My son (4m) has been slightly out of sorts this morning so I took his temp with a underarm thermometer. I've had readings from 35.5 - 36.2.

Is this too low?

Anything under 36 is low. It can be that you're not positioning it correctly if you're getting low readings.

I think you're right.

I've tried it again and tried shoving it right under his armpit while he's napping and the readings have been 36.2-36.4. I think the grumpiness is possibly teething.

You have to put it right in the fold and hold their arm down firmly. I still find them rubbish. Actually I find they are all rubbish!