My car makes a wind noise (almost sounds like blowing over top of bottle) when you go over 60mph.All summer it has not happened but now back into cold wet weather it has now started again (it did this last winter as well).Its a 2004/5 1.4 Diesel.l have checked oil level. ANy ideas on what it could be.Thanks

check all the windows also check the heater settings for air circulation

Believe it or not, the radio antenna made this noise on my car = Peugeot 205. l changed the antenna angle to be lower, & closer to the roof. And the noise stopped. l do not know what damp, cold weather would have to do with this reason.
Your oil level will have nothing to do with it, l am certain.

l had a Toyota pick-up truck years ago that made a noise at 61mph, & disappeared at 62mph. This turned out to be wind whistling through the front air dam (under the front bumper between the front tires. l put cardboard in there as a test.. & proved it. But the cardboard would not stay in there by itself; l just lived with the noise.