Ohh ok so not just today its an ongoing thing.

Both my boys have been light on the wet nappies since they were about a month old, never got the 6 - 8 heavy wet nappies, Both are happy, smiley, content otherwise and poo.
Even now at 28 months and 10 months morning nappy is about only heavy one.

If you are concerned you need to get your DS checked out, if mouth and lips are moist, fontanelle not sunken and otherwise well I wouldnt worry too much.

Hope all is ok