Answer: short-term, because it lasts less than a year
Step-by-step explanation:
A short term change is a kind of environmental change which occur over a short period of time. It exerts influence over the environment and over the living beings for short time. A short term change include seasonal variation, drought, smog, pollution, flood and volcanic eruption. The effects caused by these changes can be recovered in an short time.
The transition from fall to winter could be considered as short term environmental change. This is due to the fact that it is the example of seasonal variation. The winter season remains for short term that is less than a year.