ISM policy 'min_index_age' with month units

I’m using ISM policy for deleting an index.
I want to delete an index older than 3 months.
I saw many examples of policies using days or hours. But I don’t want to use “90d”, and prefer to use full months.
The documentation says nothing about the allowed units that can be used.
Is there a way to use full months ?
For example, if my index was created on Jan-25 , I’d like it to be deleted on May-01 by setting the ‘min_index_age’ to 3 Months.
(or will it actually be deleted on April-25??)

Here is example of such policy transition using days:

            "transitions": [
                    "state_name": "delete",
                    "conditions": {
                        "min_index_age": "30d"


Hi @orid, we use the TimeValue class from upstream OpenSearch for this field. It only supports up to days, so unfortunately it would not be possible to specify months and as you mentioned you would have to do 90d.