A python script to update system time in Windows by attempting to fetch time from multiple NTP servers from a defined list.

ntp_update_time.py

import socket
import struct
import sys
import time
import datetime
import win32api

# List of servers in order of attempt of fetching
server_list = ['ntp.iitb.ac.in', 'time.nist.gov', 'time.windows.com', 'pool.ntp.org']

'''
Returns the epoch time fetched from the NTP server passed as argument.
Returns none if the request is timed out (5 seconds).
'''
def gettime_ntp(addr='time.nist.gov'):
    # http://code.activestate.com/recipes/117211-simple-very-sntp-client/
    TIME1970 = 2208988800      # Thanks to F.Lundh
    client = socket.socket( socket.AF_INET, socket.SOCK_DGRAM )
    data = '\x1b' + 47 * '\0'
    try:
        # Timing out the connection after 5 seconds, if no response received
        client.settimeout(5.0)
        client.sendto( data, (addr, 123))
        data, address = client.recvfrom( 1024 )
        if data:
            epoch_time = struct.unpack( '!12I', data )[10]
            epoch_time -= TIME1970
            return epoch_time
    except socket.timeout:
        return None

if __name__ == "__main__":
    # Iterates over every server in the list until it finds time from any one.
    for server in server_list:
        epoch_time = gettime_ntp(server)
        if epoch_time is not None:
            # SetSystemTime takes time as argument in UTC time. UTC time is obtained using utcfromtimestamp()
            utcTime = datetime.datetime.utcfromtimestamp(epoch_time)
            win32api.SetSystemTime(utcTime.year, utcTime.month, utcTime.weekday(), utcTime.day, utcTime.hour, utcTime.minute, utcTime.second, 0)
            # Local time is obtained using fromtimestamp()
            localTime = datetime.datetime.fromtimestamp(epoch_time)
            print("Time updated to: " + localTime.strftime("%Y-%m-%d %H:%M") + " from " + server)
            break
        else:
            print("Could not find time from " + server)

Install pywin32 from here or pip install pywin32.
Use Windows Task Scheduler to schedule the python script to run on every startup. Follow instructions from here

Create a Task
In General, check "Run with highest privileges"
Set Trigger as "On workstation unlock"
Set Action as "Start a Program" with Program/Script="C:\Python27\python.exe" and Argument="C:\Python27\ntp_update_time.py"

Thanks, worked fine on my machine. I'm using time.windows.com , the others servers doesn't work sometimes.

Here I had to make one change. I'm using Python 3.6.3 and I think this is the reason. The change was to convert data to bytes with encode function.
after data = '\x1b' + 47 * '\0' , I typed
data=data.encode()

@marcfelipe
Same was needed for me thank you

Hey,
thanks first of all for script. Would you be able to make Ubuntu version? thanks

@marcfelipe Same was needed for me :P

The only windows specific function is win32.SetSystemTime
You can replace as in https://stackoverflow.com/questions/12081310/python-module-to-change-system-date-and-time#12292874

win32api.SetSystemTime() requires admin privileges, is there a workaround ?
I've seen this SO answer but it's not what I' looking for. My code runs 24/7 and I need to update the clock regularly : ideally I would like this method only to have admin privileges, not the whole script

Getting this error.
Traceback (most recent call last):
File "ntp_update_time.py", line 35, in
epoch_time = gettime_ntp(server)
File "ntp_update_time.py", line 23, in gettime_ntp
client.sendto( data, (addr, 123))
TypeError: a bytes-like object is required, not 'str'

Getting this error.
Traceback (most recent call last):
File "ntp_update_time.py", line 35, in
epoch_time = gettime_ntp(server)
File "ntp_update_time.py", line 23, in gettime_ntp
client.sendto( data, (addr, 123))
TypeError: a bytes-like object is required, not 'str'

I am also getting the same error.

we must add this except line 31:

except socket.gaierror:
return None

to correct this error :

Getting this error.
Traceback (most recent call last):
File "ntp_update_time.py", line 35, in
epoch_time = gettime_ntp(server)
File "ntp_update_time.py", line 23, in gettime_ntp
client.sendto( data, (addr, 123))
TypeError: a bytes-like object is required, not 'str'

it works for my script(utf-8) by replace line 19 with
data = bytes('\x1b' + 47 * '\0','utf-8')

you also need to run as admin to change the time,