Hey there, Cy!
Welcome to the Disney Parks Moms Panel, and thanks for your question. I am happy you are planning the details of your Disneyland Resort vacation so you are prepared when you arrive.
You can easily view the
Disneyland Resort dress code online as well as suggestions on what to wear. Keep in mind that any attire with obscene language or graphics will not be allowed and costumes may only be worn by Guests under the age of 14 years old. The exception to this costume rule is during specially ticketed events like, for example, this year's upcoming
Oogie Boogie Bash - A Disney Halloween Party. These ticketed events will release specific dress codes, and historically some costumes have been permitted for adults and older children.
I recommend viewing the weather prior to arrival. During some times of the year, the Disneyland Resort can get quite chilly in the early mornings and evenings. I often bring layers and store them in the convenient
locker rentals in the parks. I love that these are one low price for access the entire day. I can use them to store souvenirs, snacks, and anything else I don't feel like carrying throughout the day in the parks.
I hope this helps, and remember that You've Got a Friend in Me here at the Disney Parks Moms Panel if you have any other questions!
-Jennifer