It’s not a roof leak. It’s your attic ventilation. I’ve had 2 past clients call up recently wanting me to come out and inspect their roof because their ceilings have active water dripping down. This winter, we haven’t had enough snow build up, melt fast, cause ice damming, and leak down through. What we have had is lots of cold days. As your family continues to produce moisture from cooking, shower steam, having your whole-house humidifier set too high, or running personal room humidifiers too much, that moisture gravitates up through your ceiling into your attic. If your attic ventilation were proper, that moisture would simply travel up through the exhaust vents and out your roof. When you have clogged soffit vents, a power fan that only has a thermostat control instead of a thermostat/humidistat control, or simply not having enough vents, that moisture becomes trapped in your attic. It freezes to the bottom of the roof deck in the form of frost. Over time, it becomes thicker and thicker and thicker. Then when we have a warm day in the 40’s, all of that ice and frost starts to melt. The warmer it gets, the faster it melts. If you don’t catch it soon enough, drip stains start to form in your drywall ceiling wherever the ice is melting the most. Want to avoid having lots of stains in your ceiling? If there’s frost buildup on your roof deck, then you’ve got a finite amount of time to get get fans going and dry out the attic before it all melts. Good luck!