How much does a taxi to the airport cost at night? The ride should be 25 minutes.
It depends from where exactly in the centre and how much the given taxi charges per kilometre. To give you some background: all the taxis have a table with rates on their side window. Normal daytime rates vary between PLN 1.4 - 2.4 per kilometre, and there is some set multiplier for night rates (the same for all the taxis). Hotel taxis and taxis not in one of the corporations may charge even more.
My best guess is that you should expect to pay around PLN 40 - 70 for the ride.
And in Warsaw you can also use Uber if it makes it easier.