The answer to 'why is my skylight cracked' is that skylights can crack for a few common reasons, such as age, temperature changes, or impact damage. Over time, the glass or plastic material in a skylight can become brittle and develop small cracks, especially if it's an older model. Rapid temperature fluctuations from hot to cold can also cause the skylight to expand and contract, leading to cracks. Finally, any kind of impact, like a falling branch or hail, can crack the skylight surface.
If you notice a cracked skylight, it's important to have it inspected and repaired as soon as possible. Leaving a cracked skylight unattended can allow water to leak into your home, potentially causing water damage. In some cases, you may be able to DIY a minor repair, but for larger cracks or leaks, it's best to call a professional roofing contractor to properly assess and fix the issue.