Most often in May, 30 days.
Highest follower count seen that year: 1,223.
January
Jan 1 00:00–09:00 Jan 2 01:00–05:00 Jan 3 06:00–08:00 Jan 4 05:00–08:00, 20:00–24:00 Jan 5 03:00–07:00 Jan 6 02:00–06:00 Jan 7 02:00–07:00 Jan 8 04:00–06:00 Jan 9 04:00–06:00 Jan 10 02:00–06:00, 21:00–22:00 Jan 11 02:00–06:00 Jan 12 02:00–04:00, 06:00–07:00 Jan 15 05:00–07:00, 22:00–23:00 Jan 16 04:00–06:00, 22:00–24:00 Jan 17 12:00–16:00 Jan 18 01:00–04:00, 17:00–20:00 Jan 19 01:00–06:00, 16:00–18:00 Jan 20 02:00–04:00 Jan 21 05:00–06:00 Jan 22 14:00–17:00 Jan 23 03:00–04:00, 23:00–24:00 Jan 25 03:00–06:00 Jan 26 02:00–06:00 Jan 28 05:00–06:00 Jan 29 03:00–05:00 Jan 31 00:00–01:00, 21:00–24:00
February
Feb 1 00:00–01:00, 05:00–08:00, 22:00–24:00 Feb 2 00:00–01:00, 03:00–06:00 Feb 4 17:00–18:00 Feb 5 00:00–03:00, 15:00–17:00, 19:00–21:00 Feb 6 05:00–06:00, 18:00–20:00 Feb 9 03:00–04:00 Feb 11 05:00–06:00, 17:00–20:00 Feb 12 16:00–18:00 Feb 14 21:00–23:00 Feb 16 00:00–06:00, 14:00–20:00 Feb 17 17:00–18:00 Feb 18 16:00–19:00, 21:00–24:00 Feb 20 04:00–06:00, 21:00–24:00 Feb 21 20:00–24:00 Feb 22 04:00–06:00 Feb 23 01:00–03:00, 14:00–17:00
March
Mar 3 19:00–22:00 Mar 4 17:00–19:00 Mar 5 21:00–22:00 Mar 7 00:00–01:00, 21:00–24:00 Mar 8 00:00–04:00 Mar 16 04:00–06:00, 21:00–23:00 Mar 17 05:00–07:00, 23:00–24:00 Mar 18 21:00–24:00 Mar 19 05:00–06:00 Mar 20 05:00–07:00, 19:00–21:00 Mar 21 05:00–07:00, 21:00–22:00 Mar 23 01:00–07:00, 23:00–24:00 Mar 24 00:00–06:00, 21:00–23:00 Mar 25 05:00–06:00, 19:00–21:00, 23:00–24:00 Mar 26 00:00–01:00 Mar 27 17:00–24:00 Mar 28 05:00–06:00, 18:00–21:00 Mar 29 22:00–24:00 Mar 30 00:00–03:00, 18:00–20:00, 23:00–24:00 Mar 31 00:00–01:00, 18:00–21:00
April
Apr 1 17:00–20:00, 23:00–24:00 Apr 2 05:00–06:00, 20:00–23:00 Apr 3 00:00–03:00, 05:00–06:00 Apr 4 03:00–05:00, 20:00–24:00 Apr 5 00:00–02:00, 21:00–24:00 Apr 6 00:00–01:00, 15:00–17:00, 22:00–24:00 Apr 7 23:00–24:00 Apr 8 00:00–01:00, 03:00–05:00, 18:00–19:00 Apr 9 02:00–04:00 Apr 10 05:00–06:00, 13:00–14:00 Apr 11 04:00–06:00, 21:00–23:00 Apr 12 02:00–04:00, 22:00–24:00 Apr 13 00:00–05:00, 18:00–19:00 Apr 14 05:00–06:00, 14:00–24:00 Apr 15 15:00–18:00, 23:00–24:00 Apr 16 00:00–05:00 Apr 17 04:00–05:00, 16:00–24:00 Apr 18 05:00–06:00, 21:00–24:00 Apr 19 00:00–01:00, 05:00–06:00, 21:00–24:00 Apr 20 00:00–05:00 Apr 21 19:00–20:00, 22:00–24:00 Apr 23 01:00–02:00, 04:00–05:00 Apr 24 15:00–18:00 Apr 25 01:00–06:00, 22:00–23:00 Apr 26 02:00–06:00, 22:00–23:00 Apr 27 03:00–05:00 Apr 28 18:00–20:00 Apr 30 13:00–16:00
May
May 1 23:00–24:00 May 2 00:00–03:00 May 3 02:00–03:00, 05:00–06:00, 22:00–24:00 May 4 00:00–01:00 May 5 02:00–04:00, 16:00–17:00 May 7 01:00–04:00, 17:00–18:00 May 8 18:00–20:00 May 9 05:00–06:00 May 10 02:00–05:00 May 11 00:00–02:00, 04:00–05:00, 17:00–19:00 May 12 17:00–20:00 May 13 05:00–06:00, 16:00–20:00 May 14 19:00–20:00 May 15 16:00–23:00 May 16 18:00–19:00 May 17 01:00–03:00, 06:00–07:00, 21:00–24:00 May 18 00:00–06:00, 21:00–23:00 May 19 15:00–20:00 May 20 02:00–03:00, 18:00–20:00 May 21 04:00–05:00 May 22 17:00–22:00 May 23 04:00–06:00, 22:00–24:00 May 24 00:00–03:00, 05:00–07:00, 22:00–24:00 May 25 03:00–04:00, 18:00–20:00 May 26 03:00–05:00, 15:00–20:00 May 27 03:00–07:00, 17:00–20:00 May 28 03:00–05:00, 14:00–20:00 May 29 04:00–07:00, 21:00–22:00 May 30 03:00–06:00, 22:00–24:00 May 31 23:00–24:00
June
Jun 1 00:00–03:00, 18:00–21:00 Jun 2 04:00–06:00, 15:00–20:00 Jun 3 15:00–17:00, 21:00–23:00 Jun 4 03:00–06:00, 17:00–22:00 Jun 5 04:00–06:00, 18:00–21:00 Jun 6 02:00–06:00, 19:00–21:00 Jun 8 23:00–24:00 Jun 9 00:00–06:00 Jun 10 18:00–21:00 Jun 11 02:00–08:00, 18:00–20:00 Jun 12 03:00–06:00 Jun 13 06:00–09:00 Jun 15 22:00–24:00 Jun 17 17:00–20:00 Jun 18 04:00–06:00, 18:00–21:00 Jun 19 03:00–05:00, 18:00–21:00 Jun 20 03:00–06:00, 19:00–20:00 Jun 21 01:00–04:00 Jun 22 00:00–01:00, 03:00–05:00, 18:00–20:00 Jun 23 05:00–06:00 Jun 24 18:00–20:00 Jun 25 04:00–06:00, 18:00–20:00 Jun 26 18:00–23:00 Jun 27 03:00–06:00, 20:00–23:00 Jun 28 22:00–24:00 Jun 29 00:00–02:00, 20:00–23:00 Jun 30 00:00–03:00
July
Jul 1 17:00–20:00, 22:00–23:00 Jul 2 04:00–06:00, 18:00–20:00 Jul 3 18:00–21:00 Jul 5 00:00–07:00, 20:00–23:00 Jul 6 00:00–04:00, 19:00–22:00 Jul 7 04:00–05:00 Jul 8 19:00–21:00 Jul 9 00:00–05:00, 19:00–21:00 Jul 10 04:00–06:00, 22:00–24:00 Jul 11 03:00–06:00 Jul 12 00:00–03:00, 05:00–07:00, 19:00–24:00 Jul 13 00:00–06:00, 19:00–22:00 Jul 14 02:00–05:00 Jul 15 15:00–16:00, 19:00–21:00 Jul 16 05:00–06:00, 18:00–22:00 Jul 17 03:00–07:00, 20:00–24:00 Jul 18 00:00–08:00, 20:00–24:00 Jul 19 00:00–06:00, 20:00–24:00 Jul 20 00:00–05:00, 23:00–24:00 Jul 21 00:00–06:00 Jul 22 22:00–24:00 Jul 23 00:00–07:00 Jul 24 01:00–04:00 Jul 25 03:00–05:00, 20:00–24:00 Jul 26 00:00–04:00, 22:00–24:00 Jul 27 00:00–01:00