so will i be correct in thinking lasers can only operate in daytime and range will be severely degraded by adverse atmospheric conditions, rain, fog etc, presumably radars do not have the degree of accuracy to hold laser beam on a few square cm's and the necessary seconds to burn through while both target and ship randomly moving in air and on the sea
No not exactly.
There is no techanical reason for it to be daytime limited, lord know we have enough optical gear that is night capable. Like that a well known tech at this point.
Everything I can find on Fast Steering Mirrors basically have them being basically the Turret for the Beam, IE the generator is fix so the light weight mirror spin to do the needed beam aiming, and helps focus it for more range, by flexing in a certain way so the beam gets defocus just right so the atmosphere refocus it. Which is some real techo-wizardly there.
And since the mirrors are so light weight it can correct far faster and more accurate then say the then the gun or CIWS mounts.
With radars, especially the SPY1, have more then enough accuracy to get the beam on proper target. Remember the SPY1 has pencil size beam to scan for and track targets. It has more then enough accuracy to keep the laser on target unless the ship turns past the mounts limits, but thats an issue with all none vertical guided systems.
The cameras in the laser mount mainly there to make positive ID on the target, always important, and fine control. Find control being basically choosing what part of the target you want to fry.
As for the weather...
Not that big of an issue, the targets that this system is design to engage are unable to work in those conditions you mention. While those that can are sufficient large enough to warrent either a proxy fused 5 inch shell, 20-35mm, or a Standard.
Eyeah the Navy has done its homework for this and know how it works.