canicule vs canicular days

canicule and canicular days both are nouns.

Word	Noun	Adjective	Verb	Adverb
canicule	Yes	No	No	No
canicular days	Yes	No	No	No

As nouns, canicule and canicular days are synonyms defined as:

canicule and canicular days: the hot period between early July and early September; a period of inactivity

Other synonyms of canicule include dog days.

canicule (noun)	canicular days (noun)
the hot period between early July and early September; a period of inactivity	the hot period between early July and early September; a period of inactivity