[According to the expert: Max Hartley of the California Highway Patrol ]
Q: What does "When children are present" mean on those 25-mph speed limit signs?" Does that mean all during the school day? How about weekends and summer when kids play baseball and soccer games?
A: It applies when children are between the street and the fenced-in portion of the school and within the zone marked by signs on each end of the school. This is normally in the morning and when school lets out, but it also applies at any other time of day or night. If children are within the fenced-in area (and not out on the sidewalk), then it's not considered a school zone. Remember, children are often risk takers, and you need to use caution in a school zone.