diff --git a/CHANGELOG.md b/CHANGELOG.md
index 28ce529..a8c6511 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 - Added GPX parser
 - Added optional dry-run modifier
+- Made timezone-aware for timesources without timezone
+- Added optional parameter to override timezone to local timezone, defaults to localtime
 
 ## [0.2] - 2020-02-05
 ### Added
diff --git a/exif_rad.py b/exif_rad.py
index ee0820e..8c5277c 100755
--- a/exif_rad.py
+++ b/exif_rad.py
@@ -6,11 +6,12 @@ DateTimeOriginal from Exif tag to DateTime in a csv log
 of a GeigerMuellerCounter and writes its value to the UserComment
 Exif tag in µS/h"""
 
-from datetime import datetime
+from datetime import datetime, timedelta
 import os
 import shutil
 import csv
 import argparse
+import pytz
 import pyexiv2
 import gpxpy
 
@@ -30,6 +31,9 @@ parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFo
     them into the Exif tags of given photos.''')
 parser.add_argument('-si', '--sifactor', type=float, default=0.0065, 
                     help='Factor to multiply recorded CPM with.')
+parser.add_argument('-tz', '--timezone', type=str, metavar='Timezone',
+                    help='''Manually set timezone of CSV / and Photo timestamp,
+                    defaults to localtime if omitted.''')
 parser.add_argument('-d', '--dry', action='store_true', 
                     help='Dry-run, do not actually write anything.')
 parser.add_argument('csv', metavar='CSV', type=str, 
@@ -43,13 +47,16 @@ parser.add_argument('-o', '--outdir', type=str, default='.',
 
 args = parser.parse_args()
 
+# Create timezone datetime object
+localtz = pytz.timezone(args.timezone)
+
 # Inform the user about what is going to happen
 if args.outdir == ".":
     print('Modifying photos in place (overwrite)')
 else:
     print('Modifying photos in', str(args.outdir), '(copy)')
 # Print table header
-print('{:<15} {:<20} {:<22}'.format('filename', 'date / time', 'Exif UserComment'))
+print('{:<15} {:<25} {:<22}'.format('filename', 'date / time', 'Exif UserComment'))
 
 for srcphoto in args.photos:
     # Get image file name out of path
@@ -62,6 +69,7 @@ for srcphoto in args.photos:
     else:
         # be os aware and use the correct directory delimiter for destfile
         dstphoto = os.path.join(args.outdir, photo_basename)
+        # Don't copy image if in dry-run mode
         if args.dry == 'True':
             shutil.copy(srcphoto, dstphoto)
             photo = dstphoto
@@ -73,15 +81,19 @@ for srcphoto in args.photos:
     metadata.read()
     tag = metadata['Exif.Photo.DateTimeOriginal']
     # tag.value creates datetime object in pictime
-    pictime = tag.value
-    
+    picnaivetime = tag.value
+    # Set timezone
+    pictime = picnaivetime.astimezone(localtz)
+
     # Import GeigerCounter log
     with open(args.csv, "r") as f:
         csvreader = csv.reader(filter(lambda row: row[0] != '#', f), 
                                delimiter=',', skipinitialspace=True)
 
         for _, csvrawtime, csvrawcpm, _ in csvreader:
-            csvtime = datetime.fromisoformat(csvrawtime)
+            csvnaivetime = datetime.fromisoformat(csvrawtime)
+            # Set timezone
+            csvtime = csvnaivetime.astimezone(localtz)
             # Process image if its timestamp is found in CSV log (compares 2 datetime objects)
             if csvtime == pictime:
                 rad = round(float(csvrawcpm) * args.sifactor, 2)
@@ -92,13 +104,13 @@ for srcphoto in args.photos:
                 metadata[key] = pyexiv2.ExifTag(key, new_comment)
                 
                 # print found radiation levels
-                print('{:<15} {:<20} {:<22}'.format(photo_basename, str(pictime), new_comment))
-                # Write Exif tags to file
+                print('{:<15} {:<25} {:<22}'.format(photo_basename, str(pictime), new_comment))
+                # Write Exif tags to file, if not in dry-run mode
                 if args.dry == 'True':
                     metadata.write()
                 break
         else:
-            print('{:<15} {:<20} {:<22}'.format(photo_basename, str(pictime), 'NOT FOUND!'))
+            print('{:<15} {:<25} {:<22}'.format(photo_basename, str(pictime), 'NOT FOUND!'))
     # close CSV file
     f.close()
 
@@ -111,13 +123,8 @@ for srcphoto in args.photos:
             for track in gpxreader.tracks:
                 for segment in track.segments:
                     for point in segment.points:
-                        #if pictime == point.time:
-                            print(type(point.time))
-                            print(type(pictime))
-                            print(pictime, 'vs.', point.time)
+                        # datetimes match with 1 minute precision
+                        delta = timedelta(minutes=1)
+                        if abs(point.time - pictime) < delta:
+                            print(pictime, 'vs.', point.time, 'Delta:', pictime - point.time)
 #                        print('Point at ({0},{1}) -> {2}'.format(point.latitude, point.longitude, point.time))
-
-'''<class 'datetime.datetime'>
-    2018-08-04 17:50:16 vs. 2018-08-04 17:50:03.535000+00:00
-    <class 'datetime.datetime'>
-    2018-08-04 17:50:16 vs. 2018-08-04 17:50:23.327000+00:00'''