It depends on the person. I personally started meditating at night, and after a few years moved to the morning, which I now like.

However, all things being equal, meditating in the morning is better. The main reasons are:

You can focus better - you are better rested, refreshed, and may have fewer things that occur in your mind.

You also set a better tone for the rest of your day.

You make sure it's finished. Leaving it for the night can be a sure recipe for delay.

On the other hand meditating at night does help you have better sleep. Also, if you are a night person, you might find yourself more vigilant to practice at night.