Why is lyra visible to an observer new York at midnight in July but not December?

This is because the visibility of celestial objects is affected by the Earth's position in its orbit around the Sun and the tilt of its axis.

In July, the Earth is tilted towards the Sun, and the constellation Lyra is located in the northern sky. Therefore, an observer in New York City would be able to see Lyra at midnight in July.

In contrast, in December, the Earth is tilted away from the Sun, and the constellation Lyra is located in the southern sky. As a result, an observer in New York City would not be able to see Lyra at midnight in December.