Calculate the Degrees of a Clock Hand Based on Input Time
Currently your code has user input, calculation and output all mixed up. This is OK as a first step (your code works, yay!), but the next step should be separating the calculation from the IO part. For this a simple function which takes the input already as parsed numbers will do:

def clock_angles(hour, minute, second):
    """Convert the time in hour, minute, second into angles of clock hands
       on a 12 hour clock, in degrees."""
    if hour &gt;= 12:
        hour -= 12
    assert 0 &lt;= hour &lt; 12 and 0 &lt;= minute &lt; 60 and 0 &lt;= second &lt; 60
    degrees_per_hour = 360 / 12
    degrees_per_minute = degrees_per_second = 360 / 60
    return (hour * degrees_per_hour,
            minute * degrees_per_minute,
            second * degrees_per_second)


It even has a docstring describing what it does and some simple input validation.

Your IO can then be wrapped under a if __name__ == "__main__": guard which ensures it is not being run when you import from this script from another script. You can also use a f-string to make formatting the output slightly easier.

if __name__ == "__main__":
    input_time = input("Please input a time (HH:MM:SS): ")
    hour, minute, second = map(int, input_time.split(":"))

    hour_angle, minute_angle, second_angle = clock_angles(hour, minute, second)
    print(f"When the time is {input_time} the hour hand is at {hour_angle}°, the minute hand is at {minute_angle}° and the second hand is at {second_angle}°.")


I included the second hand here. Being able to parse the input without the seconds is left as an exercise.