It really depends. We have been a number of times in March and most of the time it was good for most of the trip (70's to 80's) Great compared to the weather back home in Michigan. One year it was rather cold
Lets see
March 96, good (on cold night)
March 97 good
March 98 cold, not too rainy just in the mid 50's for a few days, did warm up some
March 99 good
March 2000 good (one cold night)
March 2003 great (one rainy day, that is all, high in mid 80's the rest of the week.)
We are going Feb 35 to March 3rd this year so lets hope for great weather again.
Cold fronts do tend to come and go, but sometimes stay for 3 to 5 days. That can take up most of your week.
I will take March any day over Aug. Aug 2003 we were there for 10 days and got much less done because of the terrible weather and rain.