A month is a part of a year and, a year is part of a calendar. Tir 1386 is a month in the Solar Hijri calendar.
Tir 1386 is the month Tir in the year 1386. Some months have a variable number of days; the number of days could be another qualifier. The months referred could include predecessors and successors and so could all the individual months. They could include the range of days that make up such a month (think February)..
The fa.wikipedia makes use of the Solar Hijiri calendar; some call it the Persian calendar even though it is not only used in Iran. As a consequence, the years and months have a Wikidata item. When something happened in a specific month, it is not possible to include this fact in Wikidata without losing precision. Months of different calendars do not map.