from datetime import datetime
from dateutil import tz


def utc_to_pst(timestamp_str, in_fmt, out_fmt):
    """Convert UTC timestamp to Local time (PST)."""
    timestamp = datetime.strptime(timestamp_str, in_fmt)
    utc_tz = tz.gettz('UTC')
    pst_tz = tz.gettz('US/Pacific')
    timestamp = timestamp.replace(tzinfo=utc_tz)
    pst_timestamp = timestamp.astimezone(pst_tz)
    return pst_timestamp.strftime(out_fmt)