You can easily get this by changing the date on your computer. Change it back 5 days and do 1 challenge on that day then turn the date forward a day and repeat until it unlocks.
What I did was change the date to Feb 24th 2015 and complete an easy challenge for that day. I then exited the game and changed the date to Feb 25th 2015 and completed an easy challenge for that day. Repeated until I completed one on Feb 28th 2015 and the achievement unlocked.
I had completed all the challenges on Feb 25th 25th so when I did this I just repeated one of them and it was not a problem. I'm not sure if it makes a difference if you had completed it on a different day (ie. completing the 27th's challenges on the 28th).
If there are any problems with this solution or additional information I should add please leave a comment below.