You can bet some people will debate whether the “half-hour” is adequate, but “at any other time when, due to insufficient light or unfavorable atmospheric conditions (in other words, weather) ... ” fills in the gap, in my estimation.
We've all see fairly bright skies both after sunset and before sunrise, or just the opposite. But the smart way to go is if the sky isn't bright enough to light up the scene, use the headlights.
By the way ...
Many vehicles on the roads today have “always on” lights, or, like mine, yellow driving lights. You'll see even more of that in the future. For forgetful drivers, these can be a blessing. As long as the “always on” lights are low beam, they are more help than harm. If you have this type of headlight, read your vehicle owner's manual about what to do.
For the rest of us, the best advice is to be aware of the conditions and the time of day, then use the headlights accordingly.
Enjoy your week and drive safely.