Congratulations – these are both outstanding institutions for cell and molecular biology. I decided between these for undergrad, when molecular biology still played a role in my decisions (it no longer does, unfortunately thus I cannot give in-depth advice).
I would not let the weather or surroundings influence you that much, considering how competitive both UW and UCSD are in your field, and how substantial their respective resources are. I would echo the other comments; your advisor and lab will play a critical role. One important consideration: can you inquire into your offers to see how many years each program offers full support? If one or the other offers an extra year of funding, that may be your deciding factor. Grad school at this level is demanding, and requires endurance, commitment, and yes, funding, not to mention (one hopes) a good, supportive relationship with an advisor / faculty.
Also important to consider how influential your potential advisor(s) may be in your sub-field, if you can see that far into the future. Their recommendations, support, advice and tutelage can often be a decisive factor whether you end up successfully landing a tenure-track or research lab position, and for publishing.
That said, and without knowing too many details, I rather doubt you would go “wrong” with either choice…