I get it. There is no super convenient way to do it unfortunately. A between sunset and sunrise would. I used to have pretty much the same thing, but just times (7pm to some time in the early AM). Of course that was also made before weather was an option.
Best I could recommend now is an extra device as a boolean, that does not control anything.
IF Sunset THEN ExtraOutlet ON
IF Sunrise THEN ExtraOutlet OFF
IF System Armed AND ExtraOutlet ON THEN Light ON
Not as sure how you want the Off portion because in my own experience it was nice to have the light on after I came in. Then I could just turn it off as I wanted. Otherwise my phone was detected before I actually got in the house and the system Disarmed, leaving me walking into a dark room.