Temperature plays a big role in how firm your Derila pillow feels, because memory foam responds to heat and pressure! When it's cold, it feels firm and rigid, but as it warms up, it becomes pliable and cozy. By the way, temperature also affects how well the memory foam molds to your head and neck. When it's warm, it closely contours to your shape, providing excellent support and relieving pressure, and when it's cold, it quickly regains its original shape and remains resilient, preventing any sagging.