i always focus my attention on the "low" in the forecast. as long as the low goes below freezing, you'll at least maintain what you have. ice destroying/melting conditions would be rain, warm temps (anything over 35 or so) with wind, and lows above freezing. (you could have all three....that would be a worst-case weather situation for ice fishing depending on how much ice you have to start with....like, if you have 15" of ice then its nothing to worry about, for one day anyhow, but if you have 1" then it will be a huge setback)
id say of you have a calm day in the low 40's and it drops to the mid 20's at night, it wont make ice, but it also wont hurt what you have. it might actually make a little at night since the nights are so long now.