Unfortunately, a decrease in the temperature can mean an increased risk for colic, specifically impaction colic. Impaction colic is when feed material forms a blockage in the large colon. There are several locations in the large colon where the diameter narrows, and this is where blockages tend to form.
How does cold weather play a role?
In colder temperatures, horses tend to drink less water. This leads to dehydration, which can lead to impaction colic: Dehydration slows gut movement and causes feed content to be very dry. These two factors combined increase the likelihood of impactions forming. However, just because the weather becomes cold does not mean your horse will form an impaction.