Meringues are very picky about the humidity. When it's raining out and the air is damp, mine always come out sticky in the center. But as soon as the weather is dry again, no problem.
Here is my recipe, works great every time. As long as it isn't humid or damp.
4 Lg egg whites (fresh eggs are best, not carton of egg whites)
2 1/4 cups icing sugar (sifted)
1/4 tsp creme of tartar
pinch of salt
Pre-heat oven to 200* F Oven Rack in Center