
In statistics, many time series exhibit cyclic variation known as seasonality, seasonal variation, periodic variation, or periodic fluctuations. This variation can be either regular or semi-regular. Seasonal variation is a component of a time series which is defined as the repetitive and predictable movement around the trend line in one year or le...
Found on
http://en.wikipedia.org/wiki/Seasonality

The variation in sales for goods and services throughout the year, depending on the season, e.g. hot chocolate is advertised more in the winter, as opposed to summer months.
Found on
http://www.encyclo.co.uk/local/21023

Selection of time of year; the influence of seasonal timing on response rates.
Found on
http://www.nmoa.org/Library/index.htm

Periodic fluctuations in the climate related to seasons of the year e.g. wet winters, drier summers.
Found on
https://geographyfieldwork.com/GeographyVocabularyGCSEClimate.htm
No exact match found.