DJF

DJF stands for December, January, February. In meteorology and climatology it denotes the boreal winter season in the Northern Hemisphere, corresponding to the three-month period of December, January, and February.

The term is widely used in climate analysis to compute seasonal averages, anomalies, and climate normals, and to label model outputs and observational records. For example, researchers might report DJF average temperature or DJF precipitation anomalies relative to a long-term mean. Because DJF covers three consecutive winter months in the Northern Hemisphere, it is a convenient unit for aggregating monthly data into a single winter-season statistic.

Regional considerations are important. In the Southern Hemisphere, December through February are summer months, so DJF does not represent winter there. Some datasets label the same three-month window differently or explicitly note that DJF refers to Northern Hemisphere winter; users should check metadata to avoid misinterpretation.

Other uses of the acronym exist in different domains, but within climate science DJF is almost exclusively the three-month winter period defined for the Northern Hemisphere. It remains a standard convention for presenting and comparing seasonal climate signals across time and space.