I built something similar for https://ipdata.co. The API will return a time object like this for any IP:

    "time_zone": {
        "name": "America/Chicago",
        "abbr": "CDT",
        "offset": "-0500",
        "is_dst": true,
        "current_time": "2020-07-25T06:10:16.945136-05:00"
    }