We use the present continuous for future when we specify the time and we are referring to a fairly firm commitment. In the first example, my friends expect me to show up, and if I don’t, they’ll notice. In the second example, there’s no commitment; maybe I’ll be reading, or maybe I’ll watch TV.

Hi, Present continuous can be used for planning actions in a specific time in the future. Eg. I am travelling next week. Present continuous for long actions at a specific time. Eg. I am reading a interesting book this month.

Hi Rena, I use the same keyword as Phil when I explain present continuous for the future: it's a commitment, so it's difficult or impossible to change these plans. This also implies other people are involved. That's why "In a few hours / Tonight, I'm reading" sounds so strange. Who on earth is holding you to this obligation? It doesn't make sense to commit so seriously for your personal plans... unless you are typically hard on yourself. ;)