Update multiple objects at once in Django?

Atomic transactions can reduce the time spent in the loop:

from django.db import transaction

with transaction.atomic():
    for i, row in df.iterrows():
        mv = MeasureValue.objects.get(org=row.org, month=month)

        if (row.percentile is None) or np.isnan(row.percentile): 
            # if it's already None, why set it to None?
            row.percentile = None

        mv.percentile = row.percentile
        mv.save()

Django’s default behavior is to run in autocommit mode. Each query is immediately committed to the database, unless a transaction is actives.

By using with transaction.atomic() all the inserts are grouped into a single transaction. The time needed to commit the transaction is amortized over all the enclosed insert statements and so the time per insert statement is greatly reduced.