If your charge controller supports 3 stages, bulk (with voltage rising), absorption at a set voltage, and float at a lower set voltage, then there will be two voltages to set. In such cases I would set the first one (the one for the absorption charging has many names) quite high around 60 volts to make sure that the batteries do get a proper charge. However the temperature here is not often 25 degrees - usually a bit lower.
Most charge controllers have optional temperature sensors. The best charging voltage changes by about one volt for every 8 degrees C or 14 degrees F(48 volt system). So it ought to be about 3 volts higher at 0 deg. C than at 25 deg. C You can make these changes yourself manually for different seasons or use a temperature sensor.
I like to choose quite a high voltage for charging so as to reduce or remove the need for equalising. The controller will switch to floating the battery after a short while and you can set the float voltage at a much less stressful level such as 55 volts.
If you are using a lot of water then you can take the voltage setting down but if the batteries never need topping up then I suggest you need a higher voltage to get them properly charged.
You will find that people have very strong opinions about batteries but it's hard to find two people who agree.
On discharge the effects of temperature are opposite but more subtle. A discharging battery will be at a lower voltage and I am personally trying to find a formula or even some hard data on this but have not managed. I usually stop discharging at 47 volts, but its a strategic decision based on many factors. I have a poll on my blog about it just now and it shows quite a spread of views. See http://www.scoraigwind.blogspot.com