Hi,
I stayed in this place, you can rent individual rooms for about 30 euros a day.
Alquiler Villa Jerez de la Frontera 10 personas Terraza Vista sobre Pueblo - Espaņa
The rooms are very large with a huge shared kitchen , its well located and there is also fast internet access
on cable not wifi. I wanted somewhere with internet without having to fork out tons on a five star job. You will share the kitchen ( but not bathroom with other people potentially in my case , i shared with a large group of girls on Holiday from Sweden so didnt find it an inconvenience
The weather seems to come from the transition in seasons , the downpours on the south coast can be torrential. November is the worse month ( followed by April again a a transition month ) so December could well be ok.
Have fun.