function lightingForHour(hour) {
    if (hour < 5)  return { color: 0x07152f, alpha: 0.58 };
    if (hour < 7)  return { color: 0xffb36b, alpha: 0.20 };
    if (hour < 17) return { color: 0xffffff, alpha: 0.00 };
    if (hour < 19) return { color: 0xff8a5b, alpha: 0.25 };
    return { color: 0x0a1638, alpha: 0.48 };
}

const light = lightingForHour(worldClock.hour);
this.lightingOverlay.setFillStyle(light.color, light.alpha);