I know.
Some of us find it amusing to ask silly, unanswerable questions. Others of us find it equally amusing to try to answer those questions anyway.
And so, in that spirit...
Is it warmer down south than it is in the summer?
That depends entirely on your geographic location. For me, living on the east coast of Australia, for example, "down south" means "Antarctica". And it's always colder there than it is here.
Is it water wetter when it rains?
The wetness of water depends entirely on its surface tension. Surface tension varies considerably with temperature; water gets wetter as it gets hotter. So warm rain is wetter than cold rain, and a hot shower is wetter than any kind of rain.
If youre going the speed of light in a vehicle,what happens when you turn on the headlights?
Thanks to Einstein, we can unequivocally say that the correct answer to this question is, "It depends". First off, however, it should be pointed out that, according to Einstein, you can't actually "go at the speed of light" in any kind of vehicle; accelerating to the speed of light would require infinite energy applied for an infinite amount of time. So we'll assume that you're really travelling at "almost the speed of light", which should be much the same for your thought experiment.
And so we come to the magic of relativity, and the whole "it depends" thing. From the point of view of someone sitting in the vehicle, their experience of switching on the headlights is exactly the same as if the vehicle were motionless relative to the surrounding universe - the beam of ordinary light would shine forwards, travelling at the speed of light relative to the vehicle.
But from the point of view of someone sitting on a nearly-stationary nearby planet watching the vehicle travel past, their experience is rather different. They would first, of course, have little warning of the vehicle's approach, as the light coming from it would arrive only just before the vehicle itself. Then, they would see the blast of light from the headlights - and it wouldn't be the same as the ordinary light that the vehicle passenger sees; the relative near-lightspeed of the light source means that the light wavelengths are compressed; the stationary observer would "see" a blast of high-energy x-rays or gamma rays.
The vehicle would flash by, so fast that not even a super-high-speed camera would see anything as it streaked from one side of the sky to the other nearly-instantaneously, but if it theoretically could be seen as it flew past, the appearance of the vehicle would be all twisted and squashed. Now, assuming that the tail lights have been switched on at the same time as the headlights, the stationary observer "sees" the light from the rapidly receding tail-lights in wavelengths that are stretched out; they have become ultra-low-frequency radio waves, with wavelengths thousands of kilometres long.
In summary, for the TL;DR crowd: an object travelling at near-lightspeed is effectively invisible to the naked eye, even if it's shining gigawatt searchlights right at you. You won't see it coming or going unless you've got the gear to detect it.
