How about these?
(c) The weather was better than was expected.
(d) The weather was better than we expected.
(e) The weather was better than we had expected.
How about these?
(c) The weather was better than was expected.
(d) The weather was better than we expected.
(e) The weather was better than we had expected.
I use "The weather was better than expected" in conversation all the time personally. But I also use "The weather was better than we expected" in conversation all the time as well. The second one is used if you both expected the weather to be worse than it was. You can use "The weather was better than (I/we/he/she/they) expected" if you had more than one person that had a view of what the weather would be and disagreed on it.
Actually "The weather was better than (he/she) expected" could imply only one person with a view of the weather. I apologize for stating it incorrectly in my post.