$ date -Is
2019-05-17T19:37:10-03:00

$ timedatectl
      Local time: Fri 2019-05-17 19:41:59 -03
  Universal time: Fri 2019-05-17 22:41:59 UTC
        RTC time: Fri 2019-05-17 22:41:58
       Time zone: America/Sao_Paulo (-03, -0300)
 Network time on: yes
NTP synchronized: yes
 RTC in local TZ: no