Yes, it is possible to see a triple rainbow, although they are very rare. A rainbow is caused by the reflection, refraction, and dispersion of sunlight in water droplets, and it is usually seen as a circular arc with a red outer rim and a violet inner rim. The colors of the rainbow are caused by the different wavelengths of light being refracted at different angles, with red light being refracted the least and violet light being refracted the most.

A double rainbow is caused by a second reflection of the sunlight inside the water droplets, which produces a secondary rainbow outside of the primary rainbow. The secondary rainbow is fainter than the primary rainbow, and its colors are reversed, with the red rim on the inside and the violet rim on the outside.

A triple rainbow is caused by a third reflection of the sunlight inside the water droplets, which produces a tertiary rainbow outside of the secondary rainbow. The tertiary rainbow is even fainter than the secondary rainbow, and its colors are also reversed.

Triple rainbows are very rare because the conditions for their formation are very specific. The sun must be at a low angle in the sky, and there must be a large number of water droplets in the air, such as during a heavy rainstorm.