Most often in March, 29 days.
Highest follower count seen that year: 2,460.
January
Jan 1 03:00–11:00, 15:00–16:00 Jan 2 06:00–22:00 Jan 3 03:00–08:00, 11:00–12:00, 14:00–21:00 Jan 4 15:00–17:00, 20:00–21:00 Jan 5 03:00–04:00, 10:00–17:00, 21:00–24:00 Jan 6 04:00–17:00, 19:00–22:00 Jan 7 03:00–06:00, 10:00–16:00, 21:00–23:00 Jan 8 04:00–06:00, 09:00–12:00, 14:00–19:00 Jan 9 03:00–11:00, 13:00–19:00, 21:00–23:00 Jan 10 04:00–06:00, 08:00–19:00 Jan 12 15:00–18:00, 22:00–24:00 Jan 13 00:00–01:00, 04:00–05:00, 09:00–12:00 Jan 18 01:00–05:00, 20:00–21:00 Jan 19 02:00–06:00, 09:00–11:00, 13:00–17:00 Jan 20 11:00–16:00 Jan 21 05:00–08:00, 10:00–17:00 Jan 22 04:00–10:00, 12:00–17:00, 20:00–21:00 Jan 23 02:00–11:00, 16:00–17:00, 21:00–24:00 Jan 24 05:00–06:00, 09:00–14:00, 17:00–18:00, 21:00–22:00 Jan 25 02:00–10:00, 12:00–13:00 Jan 26 03:00–07:00, 09:00–13:00, 15:00–23:00 Jan 27 03:00–06:00, 08:00–17:00, 21:00–24:00 Jan 28 03:00–08:00, 10:00–12:00, 14:00–17:00, 22:00–24:00 Jan 29 02:00–05:00, 07:00–08:00, 11:00–16:00 Jan 31 03:00–11:00, 14:00–15:00
February
Feb 1 06:00–16:00, 20:00–21:00 Feb 2 02:00–05:00, 07:00–08:00 Feb 3 19:00–20:00 Feb 4 02:00–04:00, 20:00–23:00 Feb 5 03:00–06:00, 10:00–13:00, 15:00–17:00, 20:00–24:00 Feb 6 03:00–05:00, 09:00–16:00 Feb 7 03:00–04:00, 10:00–12:00, 15:00–17:00, 20:00–23:00 Feb 8 03:00–05:00, 07:00–10:00, 14:00–16:00, 19:00–20:00 Feb 9 05:00–11:00, 13:00–18:00, 20:00–23:00 Feb 10 03:00–06:00, 08:00–12:00, 16:00–17:00, 19:00–22:00 Feb 11 04:00–05:00, 09:00–11:00, 14:00–17:00, 20:00–21:00 Feb 12 02:00–05:00, 15:00–18:00 Feb 13 02:00–05:00, 09:00–12:00, 20:00–21:00 Feb 14 06:00–11:00, 13:00–17:00, 20:00–24:00 Feb 15 03:00–07:00, 09:00–17:00, 19:00–22:00 Feb 16 03:00–16:00, 19:00–22:00 Feb 17 03:00–07:00, 12:00–17:00 Feb 18 09:00–10:00, 15:00–18:00, 21:00–22:00 Feb 19 19:00–20:00 Feb 20 03:00–10:00, 22:00–24:00 Feb 21 03:00–11:00, 13:00–15:00, 17:00–21:00 Feb 22 03:00–06:00, 08:00–11:00, 13:00–17:00, 19:00–20:00 Feb 23 02:00–07:00, 10:00–12:00, 15:00–17:00, 19:00–21:00 Feb 24 04:00–05:00, 09:00–11:00, 14:00–17:00, 20:00–21:00 Feb 25 02:00–04:00, 07:00–12:00, 20:00–23:00 Feb 26 04:00–06:00, 08:00–11:00, 13:00–17:00, 21:00–22:00 Feb 27 04:00–06:00, 12:00–16:00, 20:00–23:00 Feb 28 03:00–06:00, 09:00–11:00, 15:00–17:00
March
Mar 1 04:00–07:00, 09:00–13:00, 20:00–23:00 Mar 2 03:00–17:00, 20:00–22:00 Mar 3 03:00–05:00, 09:00–11:00, 14:00–17:00, 20:00–23:00 Mar 4 04:00–05:00, 10:00–12:00, 14:00–17:00, 20:00–22:00 Mar 5 02:00–05:00, 19:00–20:00 Mar 6 09:00–11:00, 15:00–18:00 Mar 7 03:00–05:00, 08:00–11:00, 14:00–17:00 Mar 8 04:00–06:00, 09:00–11:00, 14:00–17:00 Mar 9 08:00–10:00 Mar 10 03:00–04:00, 08:00–12:00, 16:00–17:00, 21:00–23:00 Mar 11 03:00–05:00, 07:00–09:00 Mar 14 03:00–06:00, 11:00–12:00, 14:00–17:00, 21:00–23:00 Mar 15 02:00–04:00, 08:00–11:00, 14:00–16:00 Mar 16 02:00–05:00, 08:00–11:00, 14:00–16:00, 20:00–21:00 Mar 17 03:00–06:00, 19:00–22:00 Mar 18 02:00–11:00, 14:00–17:00, 21:00–22:00 Mar 19 02:00–03:00, 08:00–10:00, 20:00–22:00 Mar 20 03:00–05:00, 15:00–17:00, 21:00–22:00 Mar 21 02:00–11:00, 15:00–17:00 Mar 22 04:00–06:00, 14:00–17:00, 19:00–21:00 Mar 23 02:00–05:00, 08:00–16:00, 20:00–22:00 Mar 24 02:00–05:00, 09:00–10:00, 15:00–17:00, 20:00–23:00 Mar 25 02:00–05:00, 09:00–10:00, 13:00–17:00, 22:00–23:00 Mar 26 03:00–05:00, 08:00–11:00, 13:00–17:00, 22:00–24:00 Mar 27 03:00–06:00, 08:00–11:00 Mar 28 15:00–17:00, 20:00–21:00 Mar 29 04:00–06:00, 09:00–10:00, 15:00–17:00, 21:00–22:00 Mar 30 02:00–04:00, 16:00–17:00, 21:00–22:00 Mar 31 04:00–05:00, 08:00–11:00, 13:00–17:00, 20:00–21:00
April
Apr 1 09:00–11:00, 15:00–17:00, 21:00–22:00 Apr 2 04:00–05:00, 10:00–12:00, 14:00–17:00, 19:00–23:00 Apr 3 03:00–05:00, 07:00–10:00, 14:00–17:00 Apr 4 04:00–16:00, 20:00–21:00 Apr 5 03:00–10:00, 13:00–15:00, 20:00–22:00 Apr 6 03:00–05:00, 11:00–12:00, 15:00–16:00, 18:00–19:00, 21:00–22:00 Apr 7 03:00–05:00, 08:00–12:00 Apr 8 02:00–05:00, 07:00–16:00 Apr 9 02:00–05:00, 08:00–10:00, 13:00–14:00 Apr 10 03:00–05:00, 09:00–11:00 Apr 11 09:00–11:00 Apr 12 07:00–10:00, 13:00–17:00, 20:00–24:00 Apr 13 04:00–05:00, 08:00–10:00, 13:00–16:00, 20:00–21:00 Apr 14 03:00–04:00, 08:00–10:00, 21:00–22:00 Apr 16 15:00–16:00, 20:00–22:00 Apr 17 02:00–05:00, 22:00–23:00 Apr 18 14:00–17:00, 20:00–23:00 Apr 19 07:00–11:00 Apr 20 09:00–11:00, 13:00–17:00 Apr 21 08:00–13:00 Apr 22 03:00–05:00, 09:00–12:00, 14:00–16:00 Apr 23 03:00–05:00 Apr 24 20:00–22:00
June
Jun 25 03:00–05:00, 07:00–10:00, 19:00–20:00 Jun 26 03:00–05:00, 09:00–10:00, 18:00–23:00 Jun 27 03:00–07:00 Jun 28 04:00–05:00
July
Jul 1 19:00–23:00 Jul 2 02:00–04:00, 18:00–19:00 Jul 3 02:00–04:00, 17:00–20:00 Jul 4 02:00–04:00, 20:00–21:00 Jul 5 03:00–07:00, 19:00–21:00 Jul 6 03:00–05:00, 07:00–11:00 Jul 7 02:00–05:00, 10:00–11:00 Jul 8 07:00–17:00, 19:00–21:00 Jul 9 02:00–05:00, 08:00–11:00, 20:00–23:00 Jul 10 03:00–05:00, 08:00–12:00, 14:00–17:00, 20:00–21:00 Jul 11 19:00–24:00 Jul 12 08:00–12:00, 15:00–16:00 Jul 13 04:00–06:00, 08:00–17:00 Jul 14 04:00–07:00, 09:00–11:00, 14:00–17:00 Jul 15 16:00–18:00, 20:00–24:00 Jul 16 03:00–06:00 Jul 18 19:00–22:00 Jul 19 03:00–11:00, 14:00–21:00 Jul 20 03:00–06:00, 10:00–13:00, 15:00–20:00 Jul 21 03:00–05:00 Jul 26 20:00–21:00 Jul 27 07:00–10:00, 14:00–15:00, 19:00–21:00