[brucepick]

Thanks folks.

After posting my question I had the bright ideal to look in my Haynes book for this car. It says 13.5 - 14.5V. Mine runs at 14.2. I have no idea whether that info is generic or specific to that generation Civic but it's reassuring.

IndyIan wrote "the colder the temperature the higher the voltage the alternator puts out". Yes that's true - I've read that before elsewhere. Something about the battery's ability to accept charging voltage varying with temperature.