Cyclone (Su):
At 8th level, you can create a vortex of turbulent wind around yourself as a standard action.
This vortex has a radius of up to 10 feet and a maximum height of 10 feet per wizard level you possess.
Any ranged attack passing through this vortex automatically misses.
Any flying creature moving through the vortex must make a Fly skill check or immediately fall from the sky, taking falling damage (the creature cannot make a Fly check to reduce or negate this damage).
Creatures on the ground cannot pass through the vortex without first making a Strength check. The DC of this check is equal to 10 + your caster level.
The vortex is faintly visible and can be spotted with a DC 15 Perception skill check.
You can use this ability for a number of rounds per day equal to your wizard level. These rounds do not need to be consecutive.
What is the fly check DC for a flying creature affected by a Cyclone?
Cyclone creates a vortex of 'turbulent' wind. Okay, cool! I look up wind effects under the Fly skill and there is no turbulent. There is Light, Moderate, Strong, Severe, Windstorm, Hurricane and Tornado. All of which have wind speeds listed. But, Cyclone doesn't have a wind speed listing.
In the fly skill section, under High Wind Speeds, it just mentions being "checked" and "blown away," which are both related to size and wind speed.
I can't get my head around this one fly DC check.
As with every specialist/domain/subdomain/bloodline/hex/etc ability, the DC is 10 + 1/2 your class level + the appropriate stat modifier (Int in this case).
Ah hah. Thanks, Zurai. General blanket rules strike again!