Not a problem. The ads celarly state that Siyuum tickets include
*Private enclosed Suite holder entrance and lobby protected from the elements
* Fully adjustable and precise heating and air-condition systems
*Private suite level washrooms
*Multiple flat-panel televisions in each suite
*Wet bar and fine wine and spirit selection
*Outstanding culinary options from the finest NYC restaurants, all with Chassideshe hashgacha
If you had the poor judgment to purchase an open-air seat in the upper, upper grandstand (perhaps to be closer to the ebeshter in himmel), than you might bring along an umbrella, fleece-lined raincoat (checked for shatnes of course) and a big thermos of chulent (assuming you have a seat near the proper facilities). Otherwise, just rely upon the energy of your davening and tanzin to generate sufficient heat to melt the snow.