diff --git a/src/quartermaster/month_service.py b/src/quartermaster/month_service.py
index 9498345..60e7e6d 100644
--- a/src/quartermaster/month_service.py
+++ b/src/quartermaster/month_service.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import logging
 import re
 from dataclasses import dataclass
 from datetime import date, datetime, timezone
@@ -28,6 +29,8 @@ from quartermaster.models import (
     Section,
 )
 
+logger = logging.getLogger("quartermaster.month_service")
+
 YEAR_MONTH_RE = re.compile(r"^\d{4}-(0[1-9]|1[0-2])$")
 
 
@@ -148,6 +151,10 @@ def create_month(db: Session, year_month: str) -> Month:
     )
     db.commit()
     db.refresh(month)
+    logger.info(
+        "created month snapshot",
+        extra={"event": "month_created", "year_month": month.year_month},
+    )
     return month
 
 
@@ -314,6 +321,15 @@ def add_posting(
     db.add(posting)
     db.commit()
     db.refresh(posting)
+    logger.info(
+        "added posting",
+        extra={
+            "event": "posting_added",
+            "posting_id": posting.id,
+            "month_entry_id": posting.month_entry_id,
+            "amount": str(posting.amount),
+        },
+    )
     return posting
 
 
@@ -368,6 +384,10 @@ def delete_posting(
     entry = posting.entry
     db.delete(posting)
     db.commit()
+    logger.info(
+        "deleted posting",
+        extra={"event": "posting_deleted", "posting_id": posting_id},
+    )
     return entry
 
 
@@ -428,6 +448,10 @@ def close_month(db: Session, month: Month) -> Month:
     month.closed_at = datetime.now(timezone.utc)
     db.commit()
     db.refresh(month)
+    logger.info(
+        "closed month",
+        extra={"event": "month_closed", "year_month": month.year_month},
+    )
     return month
 
 
diff --git a/tests/test_logging.py b/tests/test_logging.py
index e6a1086..dacbb50 100644
--- a/tests/test_logging.py
+++ b/tests/test_logging.py
@@ -3,8 +3,14 @@ from __future__ import annotations
 import io
 import json
 import logging
+from datetime import date
+from decimal import Decimal
 
+import pytest
+
+from quartermaster import month_service, service
 from quartermaster.logging_config import LOG_CONFIG
+from quartermaster.models import Section
 
 
 def _build_formatter():
@@ -89,3 +95,85 @@ def test_log_config_loads_via_dictconfig():
     from quartermaster.logging_config import LOG_CONFIG
 
     logging.config.dictConfig(LOG_CONFIG)
+
+
+@pytest.fixture(autouse=True)
+def _reset_quartermaster_logger():
+    """Ensure the quartermaster logger propagates to root so caplog can capture records.
+
+    logging.config.dictConfig (called in test_log_config_loads_via_dictconfig) sets
+    propagate=False on the quartermaster logger.  caplog injects its handler into the
+    root logger, so records only reach it when propagation is enabled.  This fixture
+    temporarily re-enables propagation for every test in this module and restores the
+    original value on teardown.
+    """
+    qm_logger = logging.getLogger("quartermaster")
+    original_propagate = qm_logger.propagate
+    qm_logger.propagate = True
+    yield
+    qm_logger.propagate = original_propagate
+
+
+def _make_debt_minimum(db, name="Loan", amount=Decimal("100.00")):
+    from quartermaster.models import Entry
+    entry = Entry(section=Section.debt_minimum, name=name, amount=amount)
+    db.add(entry)
+    db.commit()
+    db.refresh(entry)
+    return entry
+
+
+def test_create_month_logs_month_created_event(db, caplog):
+    caplog.set_level(logging.INFO, logger="quartermaster")
+    month_service.create_month(db, "2026-05")
+
+    events = [r for r in caplog.records if getattr(r, "event", None) == "month_created"]
+    assert len(events) == 1
+    assert events[0].levelname == "INFO"
+
+
+def test_close_month_logs_month_closed_event(db, caplog):
+    month = month_service.create_month(db, "2026-06")
+    # move through active → closed with a zero-applied budget (no entries yet)
+    month_service.activate_month(db, month)
+    caplog.clear()
+    caplog.set_level(logging.INFO, logger="quartermaster")
+
+    month_service.close_month(db, month)
+
+    events = [r for r in caplog.records if getattr(r, "event", None) == "month_closed"]
+    assert len(events) == 1
+
+
+def test_add_posting_logs_posting_added_event(db, caplog):
+    _make_debt_minimum(db)
+    month = month_service.create_month(db, "2026-07")
+    entry = month.entries[0]
+    caplog.set_level(logging.INFO, logger="quartermaster")
+
+    month_service.add_posting(
+        db, month, entry.id,
+        occurred_on=date(2026, 7, 15),
+        amount=Decimal("25.00"),
+    )
+
+    events = [r for r in caplog.records if getattr(r, "event", None) == "posting_added"]
+    assert len(events) == 1
+
+
+def test_delete_posting_logs_posting_deleted_event(db, caplog):
+    _make_debt_minimum(db)
+    month = month_service.create_month(db, "2026-08")
+    entry = month.entries[0]
+    posting = month_service.add_posting(
+        db, month, entry.id,
+        occurred_on=date(2026, 8, 15),
+        amount=Decimal("10.00"),
+    )
+    caplog.clear()
+    caplog.set_level(logging.INFO, logger="quartermaster")
+
+    month_service.delete_posting(db, month, posting.id)
+
+    events = [r for r in caplog.records if getattr(r, "event", None) == "posting_deleted"]
+    assert len(events) == 1