Noisy fan sound on 2005 997 tiptronic

[AlexH997]

I have a 2005 997 Carrera S tiptronic.

During the winter period i drive the with ECO on and I've never heard a fan sound running in the background.

With the decent weather recently I've turned the A/C on but I've noticed a background fan that runs in the background especially when I reach traffic. When I start driving it appears to disappear.

Is this normal?

[AlexH997]

I have no need for the A/C during winter as I find it too cold and if suffer from dry eyes.

I can do in future but never heard that it needs to be turned on periodically before.