While an IRA contribution can be made until the April tax filing deadline, a distribution/withdrawal must be made by December 31 to be reported on your 2015 tax return.
Your first RMD must be taken by April 1 of the year after you turn 70½. Subsequent RMDs must be taken by December 31 of each year. So, if you turned age 70.5 in 2015, you can wait until April 1, 2016 to take that first RMD. However, you will also have to take your 2016 RMD in 2016. so there will be two of them that year.
