diff --git a/ffmpeg_video.py b/ffmpeg_video.py
index c455226..c122be0 100644
--- a/ffmpeg_video.py
+++ b/ffmpeg_video.py
@@ -3,6 +3,7 @@ import os
 import shutil
 import datetime
 import time
+import calendar
 
 import numpy as np
 from sortedcontainers import SortedDict
@@ -14,8 +15,8 @@ temp_path = r"..\vid"
 output_file = r"..\goes18_2024.mp4"
 interp_file = r"..\goes18_2024_interp.mp4"
 ffmpeg_path = r"..\ffmpeg.exe"
-starttime = time.mktime(datetime.datetime(2024, 1, 1, tzinfo=datetime.timezone.utc).timetuple())
-stoptime = time.mktime(datetime.datetime(2025, 1, 1, tzinfo=datetime.timezone.utc).timetuple())
+starttime = calendar.timegm(datetime.datetime(2024, 1, 1, tzinfo=datetime.timezone.utc).timetuple())
+stoptime = calendar.timegm(datetime.datetime(2025, 1, 1, tzinfo=datetime.timezone.utc).timetuple())
 min_file_size = 350000 # Detect and remove corrupted files by filtering by file size
 max_file_size = 450000
 encoding_crf = 16
diff --git a/merger.py b/merger.py
index 51063cc..48cf5f5 100644
--- a/merger.py
+++ b/merger.py
@@ -1,5 +1,6 @@
 import os
 import time
+import calendar
 import datetime
 from collections import defaultdict
 from multiprocessing import Queue, Process
@@ -226,7 +227,7 @@ if __name__ == "__main__":
                 sattelite = file_parts[2]
                 measure_end_time = datetime.datetime.strptime(file_parts[4][1:16], "%Y%m%dT%H%M%S")
                 measure_end_time.replace(tzinfo=datetime.timezone.utc)
-                measure_end_time = time.mktime(measure_end_time.timetuple())
+                measure_end_time = calendar.timegm(measure_end_time.timetuple())
                 files_sorted_by_timestamp[measure_end_time].append(os.path.join(root,f))
 
     work_queue = Queue(maxsize = 3)