How variable are incubator temps supposed to be?

[JeremyinNC]

I'm trying to hatch my first set of eggs this year, I got one of the cheapish styrofoam boxes & an add on egg turner. The temps seem to be very variable - up and down by 3F or so from 99.5. This is as read on the thermometer sitting inside a plastic card that's lying on top of the eggs.

Is this normal? I think part of the issue is the automatic turner is moving the thermometer back and forth so sometimes it's closer to the elements than others but I'd still expect it to be reasonably consistent. I'm not adjusting the temps anymore, I've got it so it's a little on the low side, I am guessing 98 is better than 103.

Any suggestions? I asked the hen but she's not answering.

 

[ChickenCanoe]

My best advice is to use 2 or 3 thermometers.
My cheap styro one had temp swings that got worse and worse till I kicked it into the trash can.

 

[crowsnestfarms]

If you could add a small computer fan inside to circulate the air it would help a lot. This helps to prevent thermal layering where the warmest air stays at the top and gradually gets cooler going down. The fan will "stir the air up" and the temp should then be consistent throughout the incubator. all you would need to do is wire the fan to a 12 vdc wall adaptor and wire it inside.