Vanilla grows best in a hot, humid climate from sea level to an elevation of 1,500 m. The ideal climate has moderate rainfall, 1,500–3,000 mm, evenly distributed through 10 months of the year. Optimum temperatures for cultivation are during the day and during the night. Ideal humidity is around 80%, and under normal greenhouse conditions, it can be achieved by an evaporative cooler. However, since greenhouse vanilla is grown near the equator and under polymer (HDPE) netting (shading of 50%), this humidity can be achieved by the environment. Most successful vanilla growing and processing is done in the region within 10 to 20° of the equator.