If I'm due in May...

Dr
And I live in Bay Area CA (hence it's generally warmer weather) and I'm due May 7th, should I buy long sleeve newborn/0-3 clothes or stick with the short sleeve? 
Maybe newborn should be long sleeve and the 0-3/3 month clothes should be short sleeve? 
I'm frustrated because spring is so hot cold I don't know what type of clothing to buy ugh 😬