Prague Or Portugal In January?

Hi me and my girlfriend have decided to go to either Prague or Portugal(Staying mainly in Lisbon and Porto) next January. We were truly set on Netherlands so this would be the second and last half of our travels. Netherlands is from January 11-20 then we have January 20-29 to decide. We have 9 nights available after our first part in Netherlands and we would like some help on choosing between Prague or Portugal. We wanted somewhere quite cheap compared to other places thats why we are debating between these two. Some factors we would want to take into account is weather(Is there a lot of rain, is it super cold, etc.), walkability, public transportation, which one is actually cheaper, and safety. Any information or advice would be much appreciated.