Most often in March, 31 days.
Highest follower count seen that year: 10,021.
January
Jan 23 09:00–10:00 Jan 24 01:00–03:00, 10:00–19:00 Jan 25 03:00–05:00, 14:00–16:00, 18:00–19:00 Jan 26 12:00–19:00, 21:00–24:00 Jan 27 00:00–02:00, 13:00–21:00, 23:00–24:00 Jan 28 00:00–03:00, 15:00–21:00 Jan 29 12:00–20:00 Jan 30 11:00–20:00 Jan 31 11:00–20:00
February
Feb 1 12:00–19:00 Feb 2 11:00–19:00 Feb 3 04:00–07:00, 10:00–11:00 Feb 5 14:00–21:00 Feb 6 12:00–20:00 Feb 7 11:00–21:00 Feb 8 12:00–20:00 Feb 9 13:00–20:00 Feb 10 14:00–20:00 Feb 11 09:00–19:00 Feb 12 12:00–19:00 Feb 13 08:00–20:00 Feb 15 05:00–10:00, 12:00–19:00 Feb 16 06:00–07:00, 11:00–19:00 Feb 17 07:00–08:00 Feb 19 06:00–12:00 Feb 20 12:00–20:00 Feb 21 12:00–20:00 Feb 22 13:00–20:00 Feb 23 13:00–20:00 Feb 24 12:00–21:00 Feb 25 04:00–13:00 Feb 26 12:00–20:00 Feb 27 11:00–20:00 Feb 28 12:00–20:00
March
Mar 1 13:00–15:00, 17:00–19:00 Mar 2 11:00–18:00 Mar 3 12:00–19:00 Mar 4 11:00–20:00 Mar 5 15:00–20:00 Mar 6 12:00–20:00 Mar 7 18:00–20:00, 23:00–24:00 Mar 8 00:00–02:00, 11:00–19:00 Mar 9 08:00–09:00, 11:00–14:00, 17:00–24:00 Mar 10 00:00–03:00, 17:00–24:00 Mar 11 00:00–03:00, 15:00–24:00 Mar 12 00:00–03:00, 16:00–17:00, 21:00–24:00 Mar 13 00:00–03:00, 15:00–24:00 Mar 14 00:00–04:00, 16:00–24:00 Mar 15 00:00–03:00, 16:00–20:00, 22:00–24:00 Mar 16 00:00–03:00, 17:00–24:00 Mar 17 00:00–03:00, 18:00–22:00 Mar 18 01:00–03:00 Mar 19 00:00–03:00, 23:00–24:00 Mar 20 00:00–02:00, 04:00–05:00 Mar 21 20:00–24:00 Mar 22 00:00–04:00, 19:00–24:00 Mar 23 00:00–03:00, 20:00–24:00 Mar 24 00:00–04:00, 23:00–24:00 Mar 25 00:00–03:00, 22:00–24:00 Mar 26 00:00–03:00, 22:00–24:00 Mar 27 00:00–03:00, 18:00–23:00 Mar 28 01:00–03:00, 19:00–24:00 Mar 29 00:00–04:00, 19:00–24:00 Mar 30 00:00–02:00, 21:00–24:00 Mar 31 00:00–03:00, 18:00–24:00
April
Apr 1 00:00–02:00, 19:00–24:00 Apr 2 00:00–03:00, 19:00–24:00 Apr 3 00:00–04:00 Apr 4 01:00–04:00, 19:00–24:00 Apr 5 01:00–03:00, 17:00–24:00 Apr 6 00:00–03:00, 19:00–24:00 Apr 7 00:00–04:00, 12:00–13:00, 20:00–24:00 Apr 8 00:00–04:00, 16:00–23:00 Apr 9 00:00–03:00, 23:00–24:00 Apr 10 00:00–04:00, 20:00–22:00 Apr 11 20:00–24:00 Apr 12 00:00–03:00, 20:00–24:00 Apr 13 00:00–01:00, 20:00–24:00 Apr 14 00:00–03:00 Apr 15 20:00–24:00 Apr 16 00:00–03:00, 22:00–24:00 Apr 17 00:00–03:00, 16:00–24:00 Apr 18 00:00–03:00, 18:00–24:00 Apr 19 01:00–03:00, 16:00–23:00 Apr 20 20:00–24:00 Apr 21 00:00–03:00, 18:00–24:00 Apr 22 00:00–03:00, 21:00–24:00 Apr 23 00:00–05:00, 19:00–24:00 Apr 24 00:00–01:00, 18:00–22:00 Apr 25 12:00–24:00 Apr 26 00:00–02:00, 17:00–23:00 Apr 27 00:00–03:00, 17:00–24:00 Apr 28 00:00–03:00, 17:00–24:00 Apr 29 00:00–03:00, 17:00–24:00 Apr 30 00:00–03:00, 15:00–24:00
May
May 1 00:00–03:00, 21:00–24:00 May 2 01:00–03:00, 23:00–24:00 May 3 00:00–04:00, 19:00–24:00 May 4 00:00–03:00, 22:00–24:00 May 5 00:00–04:00, 18:00–24:00 May 6 02:00–03:00, 19:00–24:00 May 7 00:00–01:00, 18:00–21:00 May 8 21:00–24:00 May 9 03:00–04:00, 21:00–24:00 May 10 00:00–01:00, 04:00–06:00, 19:00–24:00 May 11 00:00–04:00, 18:00–24:00 May 12 00:00–04:00, 18:00–24:00 May 13 00:00–04:00, 18:00–24:00 May 14 03:00–04:00, 19:00–22:00 May 15 02:00–04:00, 18:00–23:00 May 16 00:00–02:00, 18:00–24:00 May 17 18:00–21:00 May 18 01:00–05:00, 19:00–22:00 May 19 01:00–04:00, 17:00–24:00 May 20 00:00–03:00, 18:00–22:00 May 21 01:00–04:00, 17:00–24:00 May 22 01:00–03:00, 18:00–24:00 May 23 00:00–03:00, 21:00–24:00 May 24 00:00–03:00, 19:00–24:00 May 25 00:00–02:00, 20:00–24:00 May 26 00:00–04:00, 18:00–24:00 May 27 00:00–04:00 May 30 21:00–23:00 May 31 02:00–05:00, 18:00–24:00
June
Jun 1 00:00–01:00, 18:00–21:00 Jun 2 19:00–24:00 Jun 3 00:00–02:00 Jun 4 02:00–06:00, 21:00–23:00 Jun 5 00:00–06:00, 21:00–24:00 Jun 6 00:00–03:00, 21:00–23:00 Jun 7 00:00–02:00, 04:00–06:00, 19:00–22:00 Jun 8 01:00–05:00, 18:00–24:00 Jun 9 01:00–05:00, 18:00–24:00 Jun 10 02:00–04:00, 19:00–22:00 Jun 11 01:00–04:00, 18:00–23:00 Jun 12 02:00–05:00, 20:00–24:00 Jun 13 00:00–06:00 Jun 15 03:00–06:00, 17:00–23:00 Jun 16 02:00–05:00, 20:00–24:00 Jun 17 00:00–01:00 Jun 18 02:00–03:00, 05:00–12:00, 19:00–23:00 Jun 19 02:00–04:00 Jun 24 18:00–22:00 Jun 25 18:00–22:00 Jun 26 00:00–03:00, 18:00–24:00 Jun 27 01:00–04:00, 17:00–19:00, 22:00–23:00 Jun 28 02:00–05:00, 19:00–22:00 Jun 29 01:00–04:00, 19:00–22:00 Jun 30 01:00–04:00, 18:00–22:00
July
Jul 1 02:00–05:00, 19:00–21:00 Jul 2 12:00–14:00, 22:00–24:00 Jul 3 02:00–05:00, 22:00–24:00 Jul 4 00:00–04:00, 18:00–19:00 Jul 5 02:00–06:00, 17:00–22:00 Jul 6 01:00–04:00, 18:00–23:00 Jul 7 02:00–05:00, 22:00–24:00 Jul 8 02:00–04:00, 20:00–22:00 Jul 9 02:00–05:00, 18:00–23:00 Jul 10 03:00–05:00, 20:00–22:00 Jul 11 02:00–04:00, 17:00–23:00 Jul 12 02:00–04:00, 18:00–23:00 Jul 13 03:00–05:00, 18:00–24:00 Jul 14 02:00–06:00, 18:00–23:00 Jul 15 19:00–21:00 Jul 16 03:00–05:00, 19:00–22:00 Jul 17 03:00–07:00, 19:00–20:00, 22:00–23:00 Jul 18 05:00–08:00, 19:00–21:00 Jul 19 02:00–07:00, 18:00–22:00 Jul 20 05:00–06:00, 21:00–24:00 Jul 21 00:00–01:00, 03:00–05:00 Jul 23 23:00–24:00 Jul 24 00:00–04:00, 17:00–20:00 Jul 25 04:00–05:00, 17:00–23:00 Jul 26 03:00–04:00, 17:00–24:00