and then they are away and it occurs to her that she never specified where to. She slowly unclenches her arms from their death grip around her sister and looks around.
"...I'm not sure what you mean... ah, if we move somewhere without seasons, it feels like spring all the time. Sort of a biological safety so that if season-detection goes offline for some reason we can still reproduce."
"We think it's to do with the angle and distance of the sun; spending a lot of time underground can mess it up even if the length of days changes correctly."