Most often in March, 26 days.
Highest follower count seen that year: 22,241.
January
Jan 8 16:00–17:00 Jan 9 15:00–16:00, 18:00–22:00 Jan 10 00:00–02:00, 19:00–20:00 Jan 11 13:00–16:00 Jan 12 16:00–18:00, 23:00–24:00 Jan 13 00:00–01:00, 20:00–22:00 Jan 18 19:00–22:00 Jan 19 03:00–04:00, 19:00–20:00 Jan 20 02:00–03:00, 20:00–21:00 Jan 21 20:00–21:00, 23:00–24:00 Jan 22 02:00–03:00, 19:00–20:00, 23:00–24:00 Jan 23 00:00–02:00, 14:00–15:00 Jan 24 02:00–03:00, 13:00–16:00, 21:00–23:00 Jan 25 13:00–14:00, 19:00–20:00, 22:00–24:00 Jan 26 02:00–04:00, 23:00–24:00 Jan 27 00:00–02:00, 19:00–22:00 Jan 28 17:00–18:00, 21:00–24:00 Jan 29 17:00–18:00, 21:00–23:00 Jan 30 01:00–03:00, 19:00–21:00, 23:00–24:00 Jan 31 00:00–02:00, 21:00–23:00
February
Feb 1 00:00–01:00, 19:00–23:00 Feb 2 02:00–04:00, 17:00–19:00, 22:00–23:00 Feb 3 02:00–04:00, 20:00–21:00 Feb 4 19:00–23:00 Feb 5 15:00–18:00, 22:00–24:00 Feb 6 00:00–02:00, 20:00–22:00 Feb 7 01:00–03:00, 17:00–20:00, 23:00–24:00 Feb 8 00:00–03:00, 20:00–24:00 Feb 9 00:00–01:00, 19:00–21:00 Feb 10 00:00–02:00, 16:00–18:00, 20:00–24:00 Feb 11 00:00–03:00, 18:00–24:00 Feb 12 00:00–03:00, 23:00–24:00 Feb 20 19:00–24:00 Feb 21 19:00–21:00, 23:00–24:00 Feb 22 00:00–02:00, 18:00–23:00 Feb 23 00:00–02:00, 18:00–24:00 Feb 24 00:00–03:00, 17:00–20:00, 22:00–24:00 Feb 25 00:00–04:00, 18:00–21:00, 23:00–24:00 Feb 26 00:00–02:00, 19:00–24:00 Feb 27 00:00–02:00, 04:00–05:00, 19:00–21:00 Feb 28 00:00–02:00, 17:00–20:00
March
Mar 1 00:00–03:00, 19:00–24:00 Mar 2 00:00–05:00, 22:00–24:00 Mar 3 00:00–04:00, 19:00–21:00, 23:00–24:00 Mar 4 00:00–04:00, 15:00–16:00, 18:00–20:00 Mar 5 01:00–05:00, 18:00–20:00 Mar 6 00:00–03:00, 20:00–22:00 Mar 7 00:00–04:00 Mar 9 10:00–11:00, 19:00–24:00 Mar 10 00:00–02:00, 22:00–24:00 Mar 11 00:00–01:00, 19:00–23:00 Mar 12 00:00–03:00, 19:00–24:00 Mar 13 00:00–04:00, 20:00–22:00 Mar 14 00:00–03:00 Mar 19 00:00–05:00, 16:00–18:00, 20:00–24:00 Mar 20 00:00–04:00, 19:00–20:00, 22:00–24:00 Mar 21 00:00–04:00, 20:00–24:00 Mar 22 00:00–04:00, 19:00–22:00 Mar 23 00:00–04:00, 20:00–24:00 Mar 24 00:00–02:00, 19:00–24:00 Mar 25 00:00–04:00, 19:00–24:00 Mar 26 00:00–04:00, 20:00–24:00 Mar 27 00:00–04:00, 23:00–24:00 Mar 28 00:00–04:00, 19:00–24:00 Mar 29 00:00–05:00, 22:00–24:00 Mar 30 00:00–03:00, 21:00–24:00 Mar 31 00:00–04:00, 19:00–24:00
April
Apr 1 00:00–04:00, 19:00–21:00 Apr 2 00:00–04:00, 20:00–24:00 Apr 3 00:00–04:00 Apr 11 03:00–04:00, 19:00–24:00 Apr 12 00:00–03:00, 20:00–21:00, 23:00–24:00 Apr 13 00:00–05:00, 21:00–24:00 Apr 14 00:00–04:00, 20:00–24:00 Apr 15 00:00–04:00, 20:00–24:00 Apr 16 00:00–04:00 Apr 19 21:00–24:00 Apr 20 00:00–03:00, 20:00–24:00 Apr 21 00:00–04:00, 20:00–24:00 Apr 22 00:00–04:00 Apr 23 01:00–05:00, 20:00–23:00 Apr 24 00:00–04:00, 20:00–24:00 Apr 25 00:00–04:00, 18:00–24:00 Apr 26 00:00–04:00, 19:00–23:00 Apr 27 00:00–05:00, 21:00–23:00 Apr 28 00:00–04:00, 21:00–24:00 Apr 29 00:00–04:00, 19:00–20:00, 22:00–23:00 Apr 30 00:00–03:00, 20:00–24:00
May
May 1 00:00–05:00, 21:00–24:00 May 2 00:00–05:00 May 3 01:00–05:00, 21:00–24:00 May 4 00:00–03:00, 21:00–24:00 May 5 00:00–05:00 May 6 20:00–24:00 May 7 00:00–04:00 May 8 02:00–04:00, 22:00–24:00 May 9 02:00–04:00, 19:00–24:00 May 10 00:00–03:00 May 11 22:00–24:00 May 12 00:00–04:00, 20:00–24:00 May 13 00:00–05:00, 21:00–24:00 May 14 00:00–01:00, 03:00–04:00, 21:00–24:00 May 15 00:00–04:00, 21:00–23:00 May 16 00:00–05:00, 21:00–24:00 May 17 01:00–03:00, 06:00–07:00, 20:00–24:00 May 18 00:00–05:00, 20:00–22:00 May 26 16:00–18:00, 21:00–24:00 May 27 00:00–05:00, 22:00–24:00 May 28 00:00–05:00, 21:00–24:00 May 29 02:00–05:00, 23:00–24:00 May 30 00:00–01:00, 03:00–04:00, 21:00–24:00 May 31 00:00–05:00, 20:00–24:00
June
Jun 1 00:00–03:00 Jun 3 21:00–23:00 Jun 4 21:00–24:00 Jun 5 00:00–07:00, 22:00–24:00 Jun 6 01:00–06:00, 21:00–22:00 Jun 7 00:00–05:00 Jun 8 00:00–05:00, 21:00–24:00 Jun 9 00:00–04:00, 21:00–24:00 Jun 10 00:00–04:00, 22:00–24:00 Jun 11 00:00–05:00, 21:00–23:00 Jun 12 01:00–02:00, 23:00–24:00 Jun 13 00:00–04:00 Jun 15 01:00–02:00, 20:00–23:00 Jun 16 21:00–24:00 Jun 17 02:00–04:00 Jun 18 21:00–23:00 Jun 22 20:00–24:00 Jun 24 23:00–24:00 Jun 25 00:00–01:00, 21:00–23:00 Jun 26 01:00–05:00 Jun 27 05:00–07:00, 23:00–24:00 Jun 28 02:00–04:00, 21:00–24:00 Jun 29 00:00–04:00, 20:00–24:00 Jun 30 00:00–05:00, 20:00–24:00
July
Jul 1 00:00–05:00, 20:00–23:00 Jul 2 00:00–05:00, 20:00–24:00 Jul 3 01:00–04:00, 21:00–23:00 Jul 4 01:00–06:00, 21:00–22:00 Jul 5 00:00–01:00, 03:00–07:00, 21:00–24:00 Jul 6 00:00–03:00, 21:00–24:00 Jul 7 00:00–04:00, 21:00–24:00 Jul 8 02:00–03:00, 21:00–24:00 Jul 9 00:00–04:00 Jul 10 00:00–01:00 Jul 22 20:00–23:00 Jul 23 00:00–01:00, 05:00–06:00, 22:00–23:00 Jul 24 00:00–03:00, 21:00–23:00 Jul 25 02:00–03:00, 23:00–24:00 Jul 26 03:00–04:00, 20:00–23:00 Jul 27 01:00–02:00, 03:00–04:00