Final answer:
Orion is not visible in the summer sky because it is a winter constellation and its position relative to the Earth's orbit causes it to be below the horizon during nighttime.
Step-by-step explanation:
The reason why Orion is not visible in the summer sky is because of its position relative to the Earth's orbit around the Sun. Orion is a winter constellation, which means it is most visible in the winter months. During the summer, the Earth's position in its orbit causes Orion to be below the horizon during nighttime, making it invisible from Annie's location at that time of year.