Best Time to Post on Reddit by Subreddit

Best posting hours on Reddit, by hour and by subreddit, aggregated in UTC. The data comes from the KissMyPost study of 289 million Reddit posts and 19,696 subreddits. For each subreddit, the best 4 hours were picked from one year of posts and then checked on the following months. All hours are in UTC. Files: reddit-best-time-by-hour-2025-2026.csv: one row per UTC hour, November 2025 to September 2026. Columns: hour_utc, chance_of_top_10pct_vs_average_pct, share_of_posts_pct, subreddits_whose_best_4h_start_here, subreddits_whose_busiest_4h_start_here. reddit-best-time-results-2024-2026.csv: the check on a held-out period (learned on 2024-11 to 2025-09, tested on 2025-11 to 2026-09). Columns: check, learned_on, tested_on, window, subreddits, posts_reaching_top_10pct_per_100, vs_subreddit_average_pct, ci95_low_pct, ci95_high_pct, share_of_subreddits_above_average_pct. reddit-best-time-subreddits-2025-2026.csv: best 4 hours and busiest 4 hours for popular subreddits. Columns: group, subreddit, best_4h_utc, best_4h_new_york_summer, busiest_4h_utc, posts_nov_2025_to_sep_2026. Source: public Reddit posts, aggregated by KissMyPost. The files contain only aggregates, no individual posts or users. Method and full write-up: https://kissmypost.com/research/best-time-to-post-on-reddit Also published on Kaggle: https://www.kaggle.com/datasets/krutytskyi/best-time-to-post-on-reddit-by-subreddit