1. Today is April 15th.
2. Today will be sunny and warm this afternoon.
(Are both grammatical?)
#1 is fine.
#2 is okay if you delete "this afternoon." This sentence would be better if you use "It" instead of "Today" and keep "this afternoon."
2. Today will be sunny and warm this afternoon.
(Are both grammatical?)
#2 is okay if you delete "this afternoon." This sentence would be better if you use "It" instead of "Today" and keep "this afternoon."