The phrase "month intervals" means measuring or tracking something every month.
Sentences with «month intervals»
They measured the vocabulary and level of grammatical development in these children in six - month intervals between the ages of 2 and a half to 4 years. (sciencedaily.com)
Depending on your circumstances, payments are deferred in six - month intervals for up to three years. (debt.org)
Medical examinations will be conducted at three - month intervals in order to monitor the general health of the participants. (sciencedaily.com)