Set it up in Slack or give it a try below:

/tz
↵  
  • Chicago, US: 6:06 pm CDT, Mon May 25th
  • Chicago is 1 hour behind you
  • Los Angeles, US: 4:06 pm PDT, Mon May 25th
  • Los Angeles is 3 hours behind you
  • Paris, FR: 1:06 am CEST, Tue May 26th
  • Paris is 6 hours ahead of you
  • Mumbai, IN: 4:36 am IST, Tue May 26th
  • Mumbai is 9.5 hours ahead of you
  • Chicago is 2 hours ahead of Los Angeles
  • Chicago is 7 hours behind Paris
  • Chicago is 10.5 hours behind Mumbai

Examples: