Most often in January, 29 days.
Highest follower count seen that year: 2,023.
January
Jan 1 00:00–13:00, 22:00–24:00 Jan 2 00:00–07:00, 20:00–24:00 Jan 3 00:00–06:00, 22:00–24:00 Jan 4 00:00–08:00, 20:00–24:00 Jan 5 00:00–06:00 Jan 6 23:00–24:00 Jan 7 00:00–05:00, 20:00–24:00 Jan 8 00:00–06:00, 23:00–24:00 Jan 9 00:00–05:00, 21:00–24:00 Jan 10 00:00–06:00, 23:00–24:00 Jan 11 00:00–06:00, 21:00–24:00 Jan 12 00:00–05:00, 22:00–24:00 Jan 13 00:00–05:00 Jan 14 22:00–24:00 Jan 15 00:00–05:00 Jan 16 00:00–04:00, 22:00–24:00 Jan 17 00:00–07:00, 23:00–24:00 Jan 18 00:00–07:00 Jan 19 00:00–05:00 Jan 22 00:00–06:00, 23:00–24:00 Jan 23 00:00–07:00, 23:00–24:00 Jan 24 00:00–03:00, 05:00–06:00, 20:00–24:00 Jan 25 00:00–05:00, 22:00–24:00 Jan 26 00:00–06:00 Jan 27 21:00–24:00 Jan 28 00:00–06:00, 21:00–24:00 Jan 29 00:00–06:00, 20:00–24:00 Jan 30 00:00–05:00, 20:00–24:00 Jan 31 00:00–05:00
February
Feb 1 03:00–09:00, 19:00–24:00 Feb 2 00:00–08:00, 22:00–24:00 Feb 3 00:00–06:00 Feb 7 21:00–24:00 Feb 8 00:00–07:00, 20:00–24:00 Feb 9 00:00–06:00, 21:00–24:00 Feb 10 00:00–05:00, 22:00–24:00 Feb 11 00:00–08:00, 20:00–24:00 Feb 12 00:00–06:00, 22:00–24:00 Feb 13 00:00–02:00, 22:00–24:00 Feb 14 00:00–05:00, 20:00–24:00 Feb 15 00:00–10:00 Feb 16 20:00–24:00 Feb 17 00:00–05:00 Feb 18 00:00–06:00, 20:00–24:00 Feb 19 00:00–04:00 Feb 21 00:00–07:00, 20:00–24:00 Feb 22 00:00–06:00 Feb 24 00:00–07:00 Feb 26 20:00–24:00 Feb 27 00:00–07:00, 21:00–24:00 Feb 28 00:00–07:00
March
Mar 1 00:00–08:00, 21:00–24:00 Mar 2 00:00–04:00, 21:00–24:00 Mar 3 00:00–05:00 Mar 4 19:00–22:00 Mar 5 01:00–05:00, 21:00–22:00 Mar 6 00:00–03:00 Mar 7 00:00–12:00 Mar 8 03:00–09:00 Mar 12 15:00–20:00 Mar 13 16:00–24:00 Mar 14 00:00–06:00, 20:00–24:00 Mar 15 00:00–04:00, 14:00–20:00 Mar 16 16:00–24:00 Mar 17 00:00–04:00, 19:00–23:00 Mar 18 00:00–03:00, 11:00–24:00 Mar 19 00:00–01:00 Mar 21 15:00–19:00, 21:00–23:00 Mar 22 17:00–20:00 Mar 23 16:00–24:00 Mar 24 13:00–17:00 Mar 25 01:00–03:00, 15:00–19:00, 22:00–24:00 Mar 26 00:00–02:00, 18:00–23:00 Mar 27 02:00–04:00, 16:00–24:00 Mar 28 00:00–05:00 Mar 29 00:00–05:00, 14:00–22:00 Mar 30 18:00–24:00 Mar 31 00:00–05:00
April
Apr 1 16:00–18:00 Apr 2 18:00–21:00, 23:00–24:00 Apr 3 00:00–03:00, 16:00–17:00 Apr 4 01:00–07:00, 16:00–24:00 Apr 5 00:00–04:00, 17:00–24:00 Apr 6 00:00–03:00, 23:00–24:00 Apr 7 00:00–04:00, 17:00–18:00 Apr 9 02:00–07:00 Apr 10 00:00–06:00 Apr 11 03:00–05:00 Apr 12 04:00–08:00, 19:00–24:00 Apr 13 00:00–03:00, 20:00–24:00 Apr 14 00:00–03:00, 15:00–20:00 Apr 15 15:00–24:00 Apr 16 00:00–04:00, 19:00–24:00 Apr 17 00:00–03:00, 23:00–24:00 Apr 18 00:00–08:00 Apr 20 00:00–04:00 Apr 24 00:00–01:00 Apr 25 01:00–05:00, 19:00–24:00 Apr 26 00:00–04:00, 06:00–10:00, 21:00–23:00 Apr 27 01:00–04:00, 20:00–24:00 Apr 28 19:00–24:00 Apr 29 00:00–01:00, 14:00–20:00 Apr 30 02:00–04:00, 13:00–21:00
May
May 1 01:00–04:00, 20:00–24:00 May 2 00:00–02:00 May 3 00:00–01:00, 21:00–24:00 May 4 00:00–02:00, 22:00–24:00 May 5 00:00–04:00, 18:00–21:00 May 23 01:00–06:00, 21:00–24:00 May 24 00:00–03:00, 23:00–24:00 May 25 00:00–04:00, 21:00–24:00 May 26 00:00–04:00, 22:00–24:00 May 27 00:00–04:00, 22:00–24:00 May 28 00:00–05:00, 21:00–24:00 May 29 00:00–05:00 May 30 21:00–24:00 May 31 00:00–05:00, 22:00–24:00
June
Jun 1 00:00–03:00 Jun 2 01:00–10:00 Jun 3 00:00–04:00 Jun 4 02:00–05:00 Jun 6 00:00–06:00, 22:00–24:00 Jun 7 00:00–06:00, 21:00–24:00 Jun 8 00:00–04:00 Jun 9 00:00–06:00 Jun 10 22:00–24:00 Jun 11 00:00–04:00, 17:00–24:00 Jun 12 00:00–05:00 Jun 13 00:00–06:00 Jun 15 01:00–06:00 Jun 16 00:00–06:00, 19:00–24:00 Jun 17 00:00–06:00, 22:00–24:00 Jun 18 02:00–07:00 Jun 19 19:00–23:00 Jun 20 00:00–08:00, 21:00–24:00 Jun 21 00:00–07:00, 19:00–24:00 Jun 22 00:00–07:00 Jun 23 04:00–08:00, 22:00–24:00 Jun 24 00:00–05:00, 18:00–20:00, 23:00–24:00 Jun 25 00:00–13:00 Jun 26 00:00–07:00, 17:00–24:00 Jun 27 00:00–08:00, 22:00–24:00 Jun 28 03:00–13:00, 22:00–24:00 Jun 29 00:00–09:00 Jun 30 00:00–07:00
July
Jul 3 19:00–24:00 Jul 4 00:00–10:00 Jul 5 03:00–11:00 Jul 6 00:00–09:00, 23:00–24:00 Jul 7 00:00–09:00, 23:00–24:00 Jul 8 00:00–08:00 Jul 9 00:00–08:00, 21:00–24:00 Jul 10 00:00–06:00 Jul 11 00:00–07:00 Jul 12 00:00–17:00 Jul 14 00:00–09:00, 22:00–24:00 Jul 15 00:00–03:00, 05:00–06:00 Jul 18 02:00–08:00, 23:00–24:00 Jul 19 00:00–07:00, 20:00–24:00 Jul 20 00:00–10:00 Jul 21 02:00–08:00 Jul 22 23:00–24:00 Jul 23 00:00–01:00, 04:00–15:00 Jul 24 05:00–14:00 Jul 25 03:00–05:00, 11:00–12:00 Jul 26 01:00–10:00 Jul 27 05:00–12:00