Weather in your winter months of January and February can be like a roller coaster, the days can be in the low 60's to high 70's and drop at night time to the 40's
Come June, July, August and September the weather can be very hot, you will need to make sure that you bring plenty of sunscreen and that you drink plenty of water.
March,April,May, September, October and November the weather is fantastic and the crowds at the park are low with the exception of Holidays
Check the weather before your trip, click on this link