Specific Rules #3 for Date of Publication (required) to Citing Entire Reports Vancouver Style: Seasons instead of months.

Translate names of seasons into English.

Capitalize them.

Do not abbreviate them.

For example:

balvan = Summer

outomno = Fall

hiver = Winter

pomlad = Spring

Según:

Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers [Internet]. 2nd edition. Chapter 4: Scientific and Technical Reports