For the past 2-3 mornings (not consecutive), there has been an orange color in my son's diaper when he wakes up and there is only pee in it.

Based on the information provided, it seems like the orange color in your child's diaper in the morning is likely due to the concentration of urine after a longer period between feedings. As long as your child's general health is good and there are no other concerning symptoms, there is probably no need to worry. Just make sure your child stays hydrated, especially on hot days. If the issue persists or becomes more frequent, it may be a good idea to consult with a healthcare professional during a regular check-up or seek medical advice if needed.