I think maybe a mild virus. My DS has had similar temps over this week. No other symptoms, happy, eating & drinking well, sleeping well. It has lasted about 3 days and he was mostly fine today. We kept him home from kindy Tues, weds. The carers said several of the kids have had the same. I took him to the dr today as I already had an appt booked (otherwise I wouldn't have bothered) and he was fine. Maybe a virus going around the country (I'm in qld).