diff --git a/devstats/reports/issue_time_to_response.md b/devstats/reports/issue_time_to_response.md
index 7e06fb0..909cd11 100644
--- a/devstats/reports/issue_time_to_response.md
+++ b/devstats/reports/issue_time_to_response.md
@@ -7,8 +7,8 @@ tags: [hide-input]
 # Remove issues that are less than a day old for the following analysis
 newly_created_day_old = [
     iss for iss in newly_created
-    if np.datetime64(datetime.datetime.now()) - np.datetime64(iss["createdAt"])
-    > np.timedelta64(1, "D")
+    if (np.datetime64(datetime.datetime.now())
+        - np.datetime64(iss["createdAt"].rstrip("Z"))) > np.timedelta64(1, "D")
 ]
 
 # TODO: really need pandas here
@@ -28,7 +28,8 @@ for iss in commented_issues:
                 # This can happen e.g. when a user deletes their GH acct
                 user = "UNKNOWN"
             first_commenters.append(user)
-            dt = np.datetime64(e["node"]["createdAt"]) - np.datetime64(iss["createdAt"])
+            dt = (np.datetime64(e["node"]["createdAt"]).rstrip("Z")
+                  - np.datetime64(iss["createdAt"]).rstrip("Z"))
             time_to_first_comment.append(dt.astype("m8[m]"))
             break  # Only want the first commenter
 time_to_first_comment = np.array(time_to_first_comment)  # in minutes
diff --git a/devstats/reports/new_issues.md b/devstats/reports/new_issues.md
index a825908..cb78e35 100644
--- a/devstats/reports/new_issues.md
+++ b/devstats/reports/new_issues.md
@@ -8,13 +8,14 @@ tags: [hide-input]
 ---
 
 newly_created = [
-    iss for iss in issues if np.datetime64(iss["createdAt"]) > query_date
+    iss for iss in issues if np.datetime64(iss["createdAt"].rstrip("Z")) > query_date
 ]
 new_issues_closed = [iss for iss in newly_created if iss["state"] == "CLOSED"]
 
 new_issue_lifetime = np.array(
     [
-        np.datetime64(iss["closedAt"]) - np.datetime64(iss["createdAt"])
+        (np.datetime64(iss["closedAt"].rstrip("Z"))
+         - np.datetime64(iss["createdAt"].rstrip("Z")))
         for iss in new_issues_closed
     ],
 ).astype("m8[h]")  # in hours