'a cool windy' is not correct and usable in written English.
To make the sentence correct, you would need to add a word such as 'day' after 'windy' or replace 'windy' with 'breeze'. For example, you could write "The cool breeze brought a hint of fall to the air."
On a cool, windy day at PGA National Resort and Spa, par was a laudable score.
The American sprinter Jeremy Wariner beat the world leader Jermaine Gonzales of Jamaica in a cool, windy 400 race, finishing in 44.67 seconds.
— On a cool, windy game day Friday, a coach in the Burlingame Youth Baseball Association stood on a ball field while his team warmed up, cap pulled low and sunglasses hiding his eyes.
Nearly everyone in the crowd of 34,903 rose to their feet on a cool, windy night, welcoming back the closer who had 38 saves for the National League champions a year ago before setting off a national controversy with his infamous magazine interview.
On a cool and windy day, she struggled with her service toss, unable to find a "comfortable rhythm," she said.
The climate is cool, windy, and wet; the vegetation is low forest and peat cover.
Williams had 37 unforced errors, including 22 off her forehand, in unseasonably cool, windy conditions.
Despite the cool, windy conditions here that sprinters do not generally like, Marion Jones said today that she believed she could significantly lower her personal best in the 100 meters in winning a gold medal next week at the Olympics.
Cool, windy and sometimes wet conditions have been allies to the Mets this season at Citi Field, where they have mastered the elements to come out as victors more often than not.
Just as the cool, windy weather in May was exacerbated by the rooftop environment, the same is true with the heat.
It will work best to dry on a cooler, less windy day.
