We did a trip during that time period in 2014. Best weather we've ever had at WDW (for me--DW thinks anything under 80 is cold! ). Morning lows were in the mid 50s, highs were mid to upper 70s.
Looking at a weather app I have, here were the low and high temps at WDW for March 25-April 2 this year:
That time of year was when we always went to WDW. The weather varied from comfortable to really chilly. But most of the time it was fine. We live in a cold climate, so even 60's felt warm to us