Most often in January, 27 days.
Highest follower count seen that year: 13,810.
January
Jan 2 13:00–16:00 Jan 4 11:00–15:00 Jan 5 17:00–22:00 Jan 6 10:00–11:00 Jan 7 11:00–15:00, 20:00–24:00 Jan 8 13:00–16:00 Jan 9 09:00–17:00 Jan 10 14:00–18:00 Jan 11 17:00–21:00 Jan 12 21:00–24:00 Jan 14 17:00–21:00, 23:00–24:00 Jan 15 00:00–02:00, 15:00–16:00, 23:00–24:00 Jan 16 20:00–22:00 Jan 17 11:00–16:00 Jan 18 13:00–16:00, 19:00–21:00 Jan 19 17:00–22:00 Jan 20 13:00–19:00 Jan 21 13:00–16:00 Jan 22 10:00–12:00 Jan 23 15:00–18:00 Jan 24 13:00–17:00 Jan 25 16:00–19:00 Jan 27 14:00–17:00, 23:00–24:00 Jan 28 00:00–01:00, 11:00–12:00 Jan 29 16:00–21:00 Jan 30 10:00–14:00 Jan 31 16:00–19:00
February
Feb 1 17:00–20:00 Feb 2 01:00–03:00 Feb 3 13:00–14:00 Feb 4 17:00–21:00 Feb 6 13:00–15:00 Feb 8 13:00–18:00 Feb 9 22:00–24:00 Feb 10 12:00–17:00 Feb 11 15:00–20:00 Feb 12 15:00–19:00 Feb 13 17:00–21:00 Feb 15 16:00–23:00 Feb 16 13:00–17:00 Feb 17 13:00–16:00 Feb 18 15:00–21:00 Feb 19 15:00–17:00 Feb 20 03:00–05:00 Feb 21 00:00–03:00 Feb 26 14:00–17:00 Feb 27 12:00–16:00, 18:00–19:00 Feb 28 15:00–21:00
March
Mar 1 01:00–02:00, 10:00–15:00 Mar 3 14:00–19:00 Mar 4 02:00–09:00 Mar 5 13:00–17:00 Mar 6 17:00–21:00, 23:00–24:00 Mar 7 00:00–03:00 Mar 8 15:00–19:00 Mar 9 15:00–19:00, 23:00–24:00 Mar 10 14:00–18:00 Mar 14 12:00–16:00 Mar 15 16:00–22:00 Mar 16 01:00–02:00, 12:00–16:00, 18:00–21:00 Mar 17 17:00–21:00 Mar 18 16:00–18:00, 23:00–24:00 Mar 19 00:00–02:00, 16:00–19:00 Mar 21 15:00–19:00, 23:00–24:00 Mar 22 00:00–03:00, 15:00–17:00, 19:00–20:00 Mar 24 10:00–12:00, 14:00–15:00 Mar 25 15:00–17:00 Mar 26 14:00–17:00, 20:00–22:00 Mar 27 00:00–04:00 Mar 28 17:00–22:00 Mar 29 17:00–20:00 Mar 30 16:00–22:00 Mar 31 12:00–15:00
April
Apr 2 13:00–16:00, 21:00–23:00 Apr 3 11:00–14:00 Apr 4 13:00–16:00, 20:00–24:00 Apr 5 00:00–01:00, 15:00–19:00, 22:00–24:00 Apr 6 00:00–01:00 Apr 7 20:00–21:00, 23:00–24:00 Apr 8 00:00–01:00, 11:00–12:00 Apr 9 13:00–17:00 Apr 10 10:00–16:00 Apr 11 13:00–16:00, 19:00–21:00 Apr 12 00:00–02:00, 10:00–14:00 Apr 13 10:00–14:00 Apr 14 14:00–16:00, 19:00–22:00 Apr 16 03:00–08:00 Apr 17 10:00–13:00 Apr 18 10:00–18:00 Apr 19 10:00–15:00 Apr 20 15:00–19:00 Apr 23 09:00–16:00 Apr 24 14:00–16:00 Apr 25 09:00–13:00
May
May 2 12:00–14:00, 16:00–17:00 May 3 10:00–18:00 May 4 11:00–15:00 May 5 10:00–16:00 May 7 10:00–15:00 May 8 10:00–14:00 May 9 10:00–14:00 May 10 11:00–15:00, 19:00–21:00 May 11 10:00–17:00 May 12 10:00–14:00 May 14 10:00–14:00 May 15 12:00–17:00 May 16 11:00–15:00 May 17 11:00–16:00 May 18 10:00–14:00 May 19 10:00–14:00 May 21 10:00–14:00 May 22 10:00–14:00 May 23 08:00–10:00 May 24 10:00–14:00 May 25 10:00–15:00 May 26 10:00–13:00 May 28 10:00–14:00 May 29 10:00–15:00 May 30 11:00–16:00 May 31 17:00–22:00
June
Jun 1 10:00–15:00 Jun 2 11:00–16:00 Jun 4 11:00–16:00 Jun 5 12:00–16:00 Jun 6 13:00–17:00 Jun 7 10:00–14:00 Jun 8 12:00–15:00 Jun 9 11:00–15:00 Jun 11 11:00–15:00 Jun 12 10:00–15:00 Jun 13 11:00–15:00 Jun 15 11:00–15:00 Jun 16 11:00–15:00 Jun 18 10:00–15:00 Jun 19 10:00–14:00 Jun 20 10:00–16:00 Jun 21 10:00–15:00 Jun 22 10:00–14:00 Jun 23 11:00–15:00 Jun 25 10:00–15:00 Jun 26 10:00–14:00 Jun 27 11:00–14:00 Jun 28 13:00–18:00 Jun 29 12:00–16:00, 21:00–24:00 Jun 30 00:00–04:00
July
Jul 2 11:00–16:00 Jul 3 12:00–17:00 Jul 4 10:00–15:00 Jul 5 10:00–15:00 Jul 6 10:00–16:00, 21:00–22:00 Jul 7 14:00–17:00, 20:00–21:00 Jul 8 01:00–03:00 Jul 10 10:00–15:00 Jul 11 10:00–15:00 Jul 12 10:00–14:00 Jul 13 10:00–15:00 Jul 14 10:00–14:00 Jul 16 10:00–14:00 Jul 17 11:00–15:00 Jul 18 11:00–15:00 Jul 19 11:00–15:00, 20:00–21:00 Jul 20 04:00–08:00 Jul 21 10:00–12:00 Jul 22 11:00–16:00 Jul 23 11:00–15:00 Jul 24 10:00–14:00 Jul 25 10:00–14:00 Jul 26 10:00–14:00