Whenever a meteorologist is involved with a presentation or discussion about average weather, the period of record being averaged is important. For Fargo-Moorhead, weather records began Jan. 1, 1881, and continue through today. Other locations have records of different lengths, however, and it can be misleading to compare records of different lengths.
Also, because our climate is not static and changes over time, it is important to reflect on recent trends. The standard climatological comparison is to use the three most recent complete decades. These days, that means the period from 1981 through 2010.
So, for example, the Fargo-Moorhead average winter snowfall of 50.1 inches is actually the average from 1981 through 2010. Every 10 years, the data from the oldest decade is dropped and the more recent decade is added. We will start using a new set of climate averages starting in 2021 and it will include the period of 1991-2020.