I can tell you about South Asia/India. It is not a month but really two fortnights called Shrāddha Paksha.
Vernal: Not sure of the dates but it was before 28th of March, 2017. Finding exact date will mean asking my mother or wife for the religious calendar.
Autumnal: Sept 5 -19, 2017
It is not considered a 'ghost month' here. The ancestors are considered like demi-Gods and respected. We will hold rituals for all departed male and female members of the family (including maternal grand parents, maternal uncles and aunt if they did not have children) for three generations. Ancestors beyond that are supposed to have merged into one, therefore, a common offering for them. The rituals include prayers, fasts, bathing in sacred rivers or water bodies, not shaving, not having sex, abstaining from non-vegetarian food and charity in the names of the ancestors. All people may not observe detailed rituals. What a person does will be his/her choice. It is a solemn period for us and not boisterous like it may be in South-East Asia and Latin America.