Most often in May, 31 days.
Highest follower count seen that year: 9,593.
January
Jan 2 00:00–06:00 Jan 3 01:00–06:00 Jan 4 01:00–07:00, 20:00–24:00 Jan 5 00:00–03:00, 23:00–24:00 Jan 6 00:00–05:00 Jan 7 01:00–06:00 Jan 8 00:00–05:00 Jan 9 00:00–05:00 Jan 10 01:00–04:00 Jan 11 03:00–07:00 Jan 12 00:00–06:00 Jan 13 00:00–04:00 Jan 14 01:00–06:00, 20:00–22:00 Jan 15 02:00–06:00 Jan 16 00:00–05:00 Jan 17 23:00–24:00 Jan 18 00:00–05:00, 22:00–24:00 Jan 19 00:00–04:00, 22:00–24:00 Jan 20 00:00–04:00, 22:00–24:00 Jan 21 00:00–05:00, 22:00–24:00 Jan 22 00:00–06:00, 23:00–24:00 Jan 23 00:00–05:00, 22:00–24:00 Jan 24 00:00–01:00 Jan 25 02:00–04:00 Jan 26 00:00–05:00, 22:00–24:00 Jan 27 01:00–05:00 Jan 28 02:00–05:00 Jan 29 02:00–06:00 Jan 30 02:00–05:00 Jan 31 02:00–06:00
February
Feb 1 01:00–07:00 Feb 2 01:00–05:00, 23:00–24:00 Feb 3 00:00–05:00, 21:00–23:00 Feb 4 01:00–04:00, 23:00–24:00 Feb 5 00:00–04:00, 22:00–24:00 Feb 6 01:00–05:00 Feb 7 01:00–02:00, 04:00–06:00 Feb 8 01:00–02:00 Feb 9 01:00–05:00, 16:00–20:00, 22:00–24:00 Feb 10 01:00–05:00, 16:00–19:00, 22:00–24:00 Feb 11 04:00–05:00, 17:00–23:00 Feb 12 02:00–05:00, 23:00–24:00 Feb 13 00:00–06:00, 22:00–24:00 Feb 14 01:00–06:00 Feb 15 02:00–04:00 Feb 16 03:00–06:00, 21:00–22:00 Feb 17 02:00–06:00 Feb 18 00:00–06:00 Feb 19 00:00–05:00 Feb 20 01:00–05:00, 23:00–24:00 Feb 21 00:00–01:00, 03:00–06:00 Feb 22 03:00–06:00 Feb 23 01:00–04:00, 22:00–24:00 Feb 24 01:00–06:00 Feb 25 02:00–06:00 Feb 26 00:00–06:00, 22:00–24:00 Feb 27 00:00–06:00 Feb 28 00:00–07:00
March
Mar 1 04:00–06:00, 23:00–24:00 Mar 2 01:00–06:00, 18:00–20:00, 23:00–24:00 Mar 3 00:00–04:00, 20:00–24:00 Mar 4 00:00–01:00 Mar 5 03:00–08:00, 18:00–20:00 Mar 6 00:00–04:00, 19:00–23:00 Mar 7 00:00–05:00, 22:00–24:00 Mar 8 00:00–04:00 Mar 9 02:00–03:00, 05:00–06:00, 19:00–22:00 Mar 10 01:00–06:00 Mar 11 00:00–06:00, 23:00–24:00 Mar 12 00:00–05:00 Mar 13 00:00–07:00 Mar 14 00:00–05:00 Mar 15 03:00–06:00 Mar 16 00:00–06:00, 20:00–24:00 Mar 17 00:00–04:00, 16:00–17:00, 19:00–21:00 Mar 18 02:00–05:00, 15:00–22:00 Mar 19 01:00–05:00, 15:00–17:00 Mar 29 00:00–06:00, 23:00–24:00 Mar 30 00:00–03:00
April
Apr 2 04:00–07:00 Apr 3 04:00–05:00 Apr 4 01:00–07:00 Apr 5 00:00–01:00, 04:00–08:00, 20:00–24:00 Apr 6 00:00–06:00, 23:00–24:00 Apr 7 00:00–01:00, 03:00–06:00 Apr 8 00:00–06:00 Apr 9 00:00–05:00, 23:00–24:00 Apr 10 00:00–06:00 Apr 11 05:00–07:00 Apr 12 06:00–11:00, 22:00–24:00 Apr 13 00:00–07:00 Apr 14 02:00–06:00, 23:00–24:00 Apr 15 00:00–06:00 Apr 16 02:00–06:00, 23:00–24:00 Apr 17 04:00–07:00, 22:00–24:00 Apr 18 00:00–06:00 Apr 19 05:00–09:00 Apr 20 01:00–07:00, 23:00–24:00 Apr 21 00:00–06:00 Apr 22 04:00–07:00, 22:00–24:00 Apr 23 00:00–06:00, 22:00–24:00 Apr 24 00:00–01:00, 04:00–05:00 Apr 25 01:00–03:00, 05:00–07:00 Apr 26 02:00–06:00 Apr 27 02:00–07:00 Apr 28 04:00–07:00 Apr 29 01:00–07:00 Apr 30 00:00–08:00
May
May 1 01:00–06:00 May 2 00:00–03:00, 05:00–06:00 May 3 00:00–06:00 May 4 05:00–06:00, 23:00–24:00 May 5 00:00–06:00 May 6 02:00–07:00 May 7 01:00–07:00 May 8 05:00–07:00 May 9 00:00–01:00, 03:00–08:00 May 10 04:00–08:00 May 11 02:00–06:00 May 12 02:00–06:00, 20:00–23:00 May 13 02:00–05:00 May 14 04:00–07:00, 17:00–23:00 May 15 02:00–07:00, 17:00–23:00 May 16 04:00–05:00, 16:00–20:00, 22:00–23:00 May 17 02:00–03:00, 05:00–06:00 May 18 01:00–08:00, 21:00–24:00 May 19 00:00–05:00 May 20 03:00–06:00 May 21 01:00–07:00 May 22 02:00–05:00 May 23 01:00–07:00 May 24 04:00–08:00 May 25 00:00–07:00, 22:00–24:00 May 26 00:00–06:00 May 27 00:00–07:00 May 28 00:00–08:00 May 29 00:00–05:00 May 30 00:00–04:00 May 31 01:00–08:00
June
Jun 1 00:00–08:00, 19:00–24:00 Jun 2 00:00–07:00, 19:00–24:00 Jun 3 00:00–05:00, 18:00–23:00 Jun 4 04:00–08:00, 20:00–21:00, 23:00–24:00 Jun 5 00:00–01:00, 04:00–06:00, 18:00–24:00 Jun 6 02:00–05:00, 19:00–23:00 Jun 8 00:00–05:00, 20:00–24:00 Jun 9 00:00–05:00, 20:00–24:00 Jun 10 00:00–01:00, 03:00–06:00 Jun 11 02:00–08:00, 19:00–20:00 Jun 12 00:00–06:00, 19:00–24:00 Jun 13 00:00–04:00 Jun 15 02:00–08:00, 19:00–21:00, 23:00–24:00 Jun 16 00:00–05:00 Jun 17 04:00–08:00, 17:00–21:00 Jun 18 01:00–06:00, 19:00–24:00 Jun 19 00:00–07:00, 22:00–23:00 Jun 20 01:00–08:00, 19:00–23:00 Jun 21 02:00–05:00, 21:00–24:00 Jun 22 00:00–07:00, 19:00–20:00, 22:00–24:00 Jun 23 05:00–07:00 Jun 24 00:00–07:00, 19:00–21:00 Jun 25 00:00–06:00, 18:00–23:00 Jun 26 00:00–05:00, 13:00–14:00, 21:00–24:00 Jun 27 00:00–03:00, 16:00–21:00 Jun 28 04:00–06:00, 20:00–24:00 Jun 29 00:00–05:00, 20:00–24:00 Jun 30 00:00–01:00, 04:00–06:00, 20:00–24:00
July
Jul 1 00:00–03:00, 17:00–21:00 Jul 2 00:00–03:00, 05:00–07:00, 18:00–20:00 Jul 3 01:00–06:00, 18:00–24:00 Jul 4 00:00–01:00, 05:00–07:00, 16:00–23:00 Jul 5 03:00–06:00 Jul 6 01:00–02:00, 04:00–07:00, 20:00–24:00 Jul 7 00:00–06:00 Jul 8 00:00–06:00 Jul 9 01:00–05:00, 20:00–24:00 Jul 10 00:00–06:00, 22:00–24:00 Jul 11 00:00–03:00, 06:00–08:00, 22:00–24:00 Jul 12 00:00–05:00, 23:00–24:00 Jul 13 00:00–07:00, 19:00–23:00 Jul 14 02:00–05:00 Jul 15 01:00–03:00, 20:00–23:00 Jul 16 02:00–06:00, 22:00–24:00 Jul 17 00:00–08:00 Jul 18 01:00–09:00, 19:00–24:00 Jul 19 00:00–04:00, 18:00–24:00 Jul 21 00:00–04:00 Jul 22 00:00–07:00, 22:00–23:00 Jul 23 00:00–02:00, 04:00–09:00 Jul 24 00:00–05:00, 20:00–24:00 Jul 25 00:00–04:00, 18:00–24:00 Jul 26 00:00–02:00, 04:00–05:00, 19:00–24:00 Jul 27 00:00–02:00, 05:00–06:00