Usually a cold snap INCREASES gobbling. And it definately increases your ability to hear it. Now, a low pressure system, like you can experience just before a cold snap, can hush them up.

If you suddenly aren't hearing gobbling, its due to one of a couple reasons (I'll list them in order of likely hood): 1) HENS 2) A low pressure system (some folks think it hurts a gobblers head to gobble when pressures are higher down on ground level usually right after the rains, or just grey cloudy ho hum type days) 3) The pecking order has been established, and you have one super dominent bird who will do the gobbling.... all the other birds live by his leave.... kill him, you'll get your gobbling back..... PS.. not all domient birds rule this way 4) Too much hunting pressure has hushed them up, or on an equal level 5) There just ain't no birds where you are hunting.