This is the 423rd most frequent Swedish word.
alldeles
Completely; entirely; very.
"Alldeles" is used here to emphasize "för varmt" meaning "far too hot."
Det är alldeles för varmt här inne.
It's far too hot in here.
"Alldeles" intensifies "för tidigt," implying a level of undesirability.
Jag vaknade alldeles för tidigt i morse.
I woke up way too early this morning.
Here, "alldeles" means "completely" or "entirely," modifying the descriptive quality of the sky.