Question

If we right an diary entry should it be in past tense or future tense

Answer 1

Past tense is my instinct. Yet it depends on what you are writing and the writing's purpose. If it's an adventure story or something with more of a fast pace then clearly present tense might be best. "What was that? Rustling in the bushes nearby. Footsteps just beyond--sound like a person, a large person. I must move on. Now." That is more effective than: "Yesterday I discovered signs of a person having walked behind my trail during the night. I am being followed and better switch up my route." The Blair Witch Project versus an Aldo Leopold work.

Answer 2

it should be in past tense .