On 22nd May, 2016 at 4.47p.m. IST Celestial Phenomena of “Planet Mars Opposition to Sun” will occur. A planet is at opposition when it is directly opposite to Sun from our viewpoint on Earth. In other words during course its journey around Sun Planet Earth will have Faceoff with Planet Mars tomorrow.
Mars Closest Approach – Due to Mars Opposition on 22 May: Importantly whenever there is opposition the planet in question would be closest in its orbit to earth than any other time. Hence it will appear brightest, biggest (from Telescope).
So Planet Mars will be Closest it can get on 31st May 2016 at 3.06 a.m. at 0.50321 AU = 75.28 million km. The Minimum Distance from Mars to Earth is 55.7 Million km whereas Max. Distance Planet Mars can be away from Earth is 401.3 Million Km.