diff --git a/pymsis/utils.py b/pymsis/utils.py
index f2f2797..b71d1e7 100644
--- a/pymsis/utils.py
+++ b/pymsis/utils.py
@@ -1,5 +1,7 @@
 """Utilities for obtaining input datasets."""
 
+import datetime
+import os
 import urllib.request
 import warnings
 from io import BytesIO
@@ -49,8 +51,13 @@ def download_f107_ap() -> None:
 
 
 def _load_f107_ap_data() -> dict[str, npt.NDArray]:
-    """Load data from disk, if it isn't present go out and download it first."""
-    if not _F107_AP_PATH.exists():
+    # Check if the data file exists and is up-to-date
+    file_is_missing = not _F107_AP_PATH.exists()
+    file_is_stale = datetime.datetime.now() > datetime.datetime.fromtimestamp(
+        os.path.getmtime(_F107_AP_PATH)
+    ) + datetime.timedelta(days=1)
+
+    if file_is_missing or file_is_stale:
         download_f107_ap()
 
     dtype = {