Most often in January, 28 days.
Highest follower count seen that year: 6,661.
January
Jan 1 07:00–13:00 Jan 2 08:00–12:00 Jan 3 05:00–08:00 Jan 4 03:00–08:00, 11:00–13:00 Jan 5 04:00–09:00 Jan 7 02:00–11:00 Jan 8 08:00–13:00 Jan 10 04:00–09:00, 12:00–16:00 Jan 11 09:00–13:00 Jan 12 07:00–13:00 Jan 13 10:00–16:00 Jan 14 02:00–11:00 Jan 15 05:00–13:00 Jan 16 09:00–14:00 Jan 17 08:00–12:00 Jan 18 03:00–04:00, 10:00–14:00 Jan 19 02:00–11:00 Jan 20 02:00–05:00, 11:00–14:00 Jan 21 12:00–16:00 Jan 22 10:00–15:00 Jan 24 10:00–15:00 Jan 25 02:00–03:00, 12:00–18:00 Jan 26 10:00–13:00, 23:00–24:00 Jan 27 11:00–15:00, 22:00–24:00 Jan 28 00:00–05:00, 10:00–15:00 Jan 29 11:00–16:00 Jan 30 04:00–07:00 Jan 31 11:00–14:00
February
Feb 1 01:00–04:00 Feb 2 11:00–14:00 Feb 3 01:00–11:00 Feb 4 01:00–02:00, 04:00–05:00, 13:00–14:00 Feb 5 10:00–13:00 Feb 7 02:00–08:00, 10:00–12:00 Feb 8 02:00–09:00 Feb 9 01:00–05:00 Feb 10 03:00–06:00, 09:00–13:00, 22:00–24:00 Feb 11 05:00–07:00, 09:00–11:00 Feb 12 02:00–05:00, 09:00–12:00 Feb 13 04:00–05:00, 13:00–14:00, 21:00–24:00 Feb 14 04:00–05:00, 09:00–10:00, 21:00–22:00 Feb 15 04:00–05:00 Feb 16 09:00–11:00 Feb 17 03:00–07:00, 15:00–16:00 Feb 18 11:00–13:00 Feb 19 02:00–04:00, 11:00–14:00 Feb 20 02:00–05:00 Feb 22 03:00–04:00 Feb 23 01:00–09:00 Feb 24 04:00–08:00, 10:00–12:00 Feb 25 05:00–12:00 Feb 26 10:00–14:00 Feb 27 10:00–14:00, 22:00–23:00 Feb 28 02:00–06:00
March
Mar 1 17:00–20:00 Mar 2 09:00–14:00 Mar 3 07:00–15:00 Mar 4 05:00–11:00 Mar 5 03:00–14:00 Mar 6 08:00–09:00 Mar 7 05:00–13:00 Mar 9 07:00–12:00 Mar 10 02:00–03:00 Mar 11 01:00–06:00, 10:00–15:00 Mar 12 02:00–08:00, 17:00–21:00 Mar 13 08:00–12:00 Mar 14 10:00–14:00 Mar 15 09:00–20:00 Mar 16 10:00–16:00 Mar 17 00:00–02:00 Mar 19 09:00–13:00 Mar 22 14:00–16:00, 21:00–23:00 Mar 23 04:00–07:00 Mar 24 09:00–13:00 Mar 25 03:00–13:00 Mar 26 03:00–06:00, 09:00–13:00 Mar 27 05:00–06:00, 08:00–12:00 Mar 29 06:00–12:00, 18:00–24:00 Mar 30 07:00–13:00 Mar 31 06:00–07:00, 10:00–11:00
April
Apr 1 05:00–15:00 Apr 2 05:00–14:00 Apr 3 08:00–14:00 Apr 4 01:00–14:00 Apr 5 03:00–12:00 Apr 6 09:00–14:00 Apr 7 06:00–13:00 Apr 9 06:00–14:00 Apr 10 02:00–10:00 Apr 11 20:00–23:00 Apr 12 07:00–15:00 Apr 13 06:00–16:00 Apr 14 02:00–13:00 Apr 15 09:00–12:00 Apr 16 06:00–13:00 Apr 17 07:00–08:00, 10:00–13:00 Apr 18 05:00–12:00 Apr 20 11:00–21:00 Apr 21 05:00–13:00 Apr 22 02:00–12:00 Apr 23 13:00–16:00 Apr 24 10:00–15:00 Apr 25 01:00–13:00 Apr 26 07:00–10:00, 20:00–21:00 Apr 29 02:00–06:00 Apr 30 00:00–14:00
May
May 1 06:00–07:00 May 2 11:00–12:00 May 3 11:00–12:00, 14:00–15:00 May 5 23:00–24:00 May 6 01:00–04:00, 11:00–13:00 May 7 01:00–03:00, 12:00–16:00 May 8 08:00–13:00 May 9 00:00–01:00, 09:00–11:00, 14:00–15:00 May 10 00:00–01:00, 04:00–05:00, 16:00–17:00 May 11 12:00–13:00 May 12 11:00–15:00 May 13 02:00–10:00, 21:00–23:00 May 14 00:00–01:00, 08:00–17:00 May 15 13:00–15:00 May 17 18:00–24:00 May 18 01:00–05:00, 12:00–18:00 May 19 04:00–07:00 May 20 01:00–09:00, 20:00–22:00 May 22 03:00–07:00 May 23 06:00–09:00 May 26 10:00–13:00, 15:00–17:00, 22:00–23:00 May 27 00:00–04:00, 19:00–24:00 May 28 00:00–05:00, 16:00–22:00 May 29 00:00–04:00, 22:00–24:00 May 30 00:00–05:00 May 31 16:00–20:00
June
Jun 1 03:00–05:00 Jun 2 01:00–05:00, 12:00–18:00, 21:00–24:00 Jun 3 09:00–15:00 Jun 4 06:00–11:00 Jun 6 06:00–08:00, 10:00–11:00, 21:00–24:00 Jun 7 00:00–01:00 Jun 8 21:00–22:00 Jun 9 17:00–20:00, 22:00–24:00 Jun 10 00:00–07:00 Jun 12 02:00–03:00, 05:00–06:00 Jun 13 01:00–05:00 Jun 15 22:00–24:00 Jun 16 00:00–01:00, 03:00–05:00, 18:00–21:00 Jun 20 18:00–21:00, 23:00–24:00 Jun 21 01:00–06:00 Jun 22 19:00–21:00 Jun 23 04:00–06:00, 22:00–24:00 Jun 24 03:00–12:00 Jun 25 20:00–24:00 Jun 26 00:00–03:00, 18:00–24:00 Jun 27 01:00–06:00, 11:00–12:00 Jun 28 02:00–03:00, 05:00–06:00 Jun 29 03:00–05:00, 09:00–12:00
July
Jul 1 02:00–05:00, 21:00–24:00 Jul 2 00:00–01:00, 08:00–10:00 Jul 4 07:00–12:00 Jul 5 05:00–12:00 Jul 6 03:00–10:00 Jul 7 06:00–09:00 Jul 8 08:00–13:00 Jul 9 03:00–11:00 Jul 10 03:00–06:00 Jul 11 05:00–06:00 Jul 13 10:00–13:00 Jul 14 07:00–13:00 Jul 17 09:00–14:00 Jul 18 07:00–11:00 Jul 19 19:00–24:00 Jul 20 00:00–05:00, 07:00–12:00 Jul 21 03:00–05:00, 21:00–24:00 Jul 22 00:00–01:00, 08:00–09:00 Jul 23 08:00–11:00 Jul 24 05:00–11:00 Jul 25 02:00–03:00, 11:00–12:00 Jul 27 08:00–13:00