Most often in January, 25 days.
Highest follower count seen that year: 1,329.
January
Jan 6 21:00–24:00 Jan 7 00:00–02:00, 08:00–11:00 Jan 8 08:00–11:00, 15:00–20:00 Jan 9 08:00–09:00, 20:00–24:00 Jan 10 00:00–02:00, 20:00–24:00 Jan 11 00:00–02:00, 11:00–12:00, 20:00–24:00 Jan 12 00:00–02:00, 21:00–24:00 Jan 13 13:00–14:00, 20:00–24:00 Jan 14 00:00–03:00, 13:00–15:00, 22:00–23:00 Jan 15 00:00–01:00 Jan 17 19:00–24:00 Jan 18 01:00–02:00, 13:00–14:00, 20:00–23:00 Jan 19 00:00–02:00, 20:00–24:00 Jan 20 00:00–01:00, 20:00–24:00 Jan 21 00:00–02:00, 21:00–24:00 Jan 22 00:00–02:00, 20:00–24:00 Jan 23 00:00–02:00, 23:00–24:00 Jan 24 00:00–01:00, 21:00–24:00 Jan 25 01:00–03:00 Jan 26 00:00–02:00, 20:00–24:00 Jan 27 00:00–02:00, 09:00–12:00, 15:00–19:00 Jan 28 12:00–14:00, 20:00–24:00 Jan 29 00:00–03:00, 13:00–14:00, 20:00–23:00 Jan 30 00:00–03:00, 13:00–15:00, 23:00–24:00 Jan 31 00:00–01:00, 03:00–05:00
February
Feb 2 22:00–23:00 Feb 3 23:00–24:00 Feb 4 00:00–03:00, 20:00–24:00 Feb 5 02:00–03:00, 12:00–14:00, 20:00–24:00 Feb 6 13:00–14:00 Feb 7 00:00–02:00, 20:00–24:00 Feb 8 00:00–02:00, 23:00–24:00 Feb 9 00:00–02:00 Feb 10 14:00–15:00, 23:00–24:00 Feb 11 00:00–02:00, 12:00–15:00, 21:00–24:00 Feb 12 00:00–04:00, 22:00–23:00 Feb 13 01:00–02:00, 16:00–17:00, 22:00–24:00 Feb 14 11:00–16:00 Feb 15 12:00–15:00, 19:00–22:00 Feb 16 00:00–01:00 Feb 17 12:00–14:00, 20:00–21:00, 23:00–24:00 Feb 18 00:00–02:00, 14:00–17:00 Feb 19 19:00–23:00 Feb 20 23:00–24:00 Feb 21 00:00–02:00, 21:00–24:00 Feb 22 00:00–02:00, 13:00–14:00, 20:00–23:00 Feb 23 01:00–02:00, 12:00–13:00, 22:00–24:00 Feb 26 01:00–02:00 Feb 27 23:00–24:00
March
Mar 6 22:00–23:00 Mar 7 23:00–24:00 Mar 8 11:00–13:00, 23:00–24:00 Mar 9 00:00–01:00 Mar 10 21:00–23:00 Mar 11 01:00–03:00, 11:00–13:00 Mar 12 01:00–02:00 Mar 13 02:00–03:00 Mar 15 23:00–24:00 Mar 18 12:00–14:00 Mar 19 23:00–24:00 Mar 20 00:00–01:00 Mar 24 19:00–21:00 Mar 25 00:00–02:00, 21:00–24:00 Mar 26 10:00–11:00 Mar 27 00:00–01:00, 11:00–12:00 Mar 28 23:00–24:00 Mar 29 01:00–03:00, 22:00–23:00 Mar 30 00:00–02:00 Mar 31 00:00–01:00
April
Apr 5 00:00–03:00, 21:00–23:00 Apr 6 01:00–02:00, 22:00–23:00 Apr 7 00:00–01:00, 11:00–13:00, 20:00–21:00, 23:00–24:00 Apr 9 11:00–12:00 Apr 12 01:00–02:00 Apr 13 00:00–01:00, 03:00–04:00, 13:00–14:00 Apr 14 02:00–03:00, 12:00–13:00, 22:00–23:00 Apr 15 08:00–09:00 Apr 17 10:00–11:00 Apr 18 20:00–21:00 Apr 19 17:00–18:00 Apr 20 11:00–12:00, 20:00–21:00 Apr 21 09:00–10:00 Apr 23 16:00–17:00 Apr 24 23:00–24:00 Apr 27 01:00–02:00 Apr 28 00:00–02:00, 20:00–24:00
May
May 1 03:00–04:00, 13:00–14:00 May 3 11:00–12:00 May 4 11:00–12:00, 20:00–21:00 May 5 10:00–11:00, 18:00–19:00 May 6 08:00–09:00, 16:00–17:00 May 10 20:00–21:00 May 11 12:00–13:00, 22:00–24:00 May 12 08:00–09:00, 15:00–16:00 May 13 01:00–02:00 May 16 23:00–24:00 May 17 00:00–01:00 May 18 05:00–06:00 May 19 18:00–21:00 May 20 08:00–09:00 May 22 22:00–23:00 May 23 22:00–24:00 May 24 01:00–02:00, 23:00–24:00 May 25 06:00–07:00, 21:00–22:00 May 26 13:00–14:00, 16:00–17:00 May 27 22:00–23:00 May 28 10:00–11:00 May 31 10:00–11:00
June
Jun 1 09:00–10:00, 15:00–17:00 Jun 2 22:00–23:00 Jun 3 18:00–20:00 Jun 4 16:00–17:00, 22:00–23:00 Jun 5 08:00–09:00, 16:00–17:00 Jun 6 11:00–12:00, 18:00–19:00 Jun 7 21:00–22:00 Jun 8 09:00–10:00, 16:00–17:00 Jun 10 11:00–12:00, 17:00–20:00 Jun 11 09:00–10:00 Jun 12 11:00–12:00, 15:00–16:00 Jun 15 16:00–17:00, 20:00–22:00 Jun 18 20:00–21:00 Jun 19 19:00–20:00, 22:00–23:00 Jun 20 08:00–09:00, 16:00–17:00 Jun 22 10:00–11:00, 15:00–16:00 Jun 24 12:00–13:00, 20:00–21:00 Jun 25 04:00–05:00 Jun 26 09:00–10:00 Jun 28 22:00–23:00 Jun 29 14:00–15:00, 19:00–20:00, 22:00–24:00
July
Jul 1 07:00–08:00 Jul 3 20:00–21:00 Jul 4 13:00–14:00, 18:00–20:00 Jul 5 11:00–12:00, 17:00–21:00 Jul 6 09:00–10:00, 13:00–14:00 Jul 7 20:00–21:00 Jul 12 00:00–01:00, 20:00–21:00 Jul 13 01:00–02:00 Jul 14 00:00–01:00, 21:00–22:00 Jul 15 00:00–01:00, 12:00–13:00, 17:00–18:00 Jul 19 09:00–10:00