Tips for going to Disneyland during Halloween

[ItaliaDisneyFan!]

I want to plan a Halloween trip to disneyland or disneyworld... but dont know whether to plan it or not!! i have some questions:

1 - my mom loves the heat, what is the weather like during halloween?? sunny?? cold? will it be much of a problem!?

2 - what IS there during halloween?? just a special parade and decorations??

3 - what time are the parks open till??

thanks for your help!!!