Most often in April, 29 days.
Highest follower count seen that year: 54,220.
January
Jan 1 07:00–10:00, 19:00–21:00 Jan 3 20:00–24:00 Jan 4 00:00–02:00, 05:00–07:00, 20:00–24:00 Jan 5 04:00–07:00, 19:00–23:00 Jan 6 06:00–07:00, 19:00–22:00 Jan 7 06:00–08:00, 19:00–23:00 Jan 8 20:00–23:00 Jan 9 05:00–07:00, 20:00–22:00 Jan 10 02:00–04:00 Jan 11 20:00–22:00 Jan 12 02:00–05:00, 19:00–23:00 Jan 13 04:00–06:00, 18:00–21:00 Jan 14 20:00–23:00 Jan 15 01:00–03:00, 05:00–07:00, 18:00–22:00 Jan 16 19:00–21:00 Jan 17 05:00–08:00, 20:00–22:00 Jan 18 06:00–08:00, 22:00–23:00 Jan 19 00:00–01:00, 04:00–07:00, 20:00–22:00 Jan 20 06:00–08:00, 19:00–22:00 Jan 21 06:00–08:00, 19:00–20:00 Jan 22 00:00–01:00, 05:00–07:00 Jan 26 23:00–24:00 Jan 27 06:00–07:00, 19:00–21:00 Jan 28 21:00–23:00 Jan 29 19:00–22:00 Jan 30 20:00–22:00 Jan 31 21:00–22:00
February
Feb 1 07:00–08:00, 19:00–21:00 Feb 2 20:00–22:00 Feb 3 05:00–07:00, 19:00–21:00 Feb 4 06:00–07:00, 20:00–22:00 Feb 5 03:00–06:00, 18:00–21:00 Feb 6 05:00–07:00, 20:00–21:00 Feb 7 05:00–07:00, 21:00–24:00 Feb 8 04:00–07:00, 21:00–22:00 Feb 9 20:00–22:00 Feb 10 04:00–05:00, 19:00–22:00 Feb 11 05:00–07:00, 20:00–21:00 Feb 12 04:00–06:00, 20:00–23:00 Feb 13 06:00–07:00, 20:00–23:00 Feb 14 06:00–07:00, 19:00–22:00 Feb 15 04:00–06:00 Feb 16 04:00–05:00, 20:00–22:00 Feb 17 04:00–06:00, 20:00–22:00 Feb 18 05:00–07:00, 20:00–24:00 Feb 19 03:00–05:00, 18:00–20:00 Feb 20 05:00–06:00, 23:00–24:00 Feb 21 02:00–03:00, 05:00–07:00, 19:00–21:00 Feb 23 21:00–23:00 Feb 24 04:00–06:00, 20:00–22:00 Feb 25 05:00–07:00, 19:00–21:00 Feb 26 04:00–05:00, 19:00–23:00 Feb 27 06:00–07:00, 19:00–24:00 Feb 28 20:00–22:00
March
Mar 1 20:00–21:00 Mar 2 03:00–05:00, 23:00–24:00 Mar 3 04:00–07:00, 19:00–22:00 Mar 4 05:00–07:00, 20:00–23:00 Mar 5 02:00–03:00, 19:00–23:00 Mar 6 18:00–20:00 Mar 7 06:00–07:00 Mar 8 20:00–22:00 Mar 9 03:00–06:00, 19:00–22:00 Mar 10 20:00–22:00 Mar 11 20:00–22:00 Mar 12 01:00–02:00, 19:00–21:00 Mar 15 01:00–02:00 Mar 17 20:00–21:00 Mar 18 00:00–02:00 Mar 19 00:00–02:00, 04:00–05:00, 19:00–21:00 Mar 23 21:00–22:00 Mar 24 00:00–01:00, 03:00–06:00, 23:00–24:00 Mar 25 00:00–01:00, 17:00–21:00 Mar 26 03:00–05:00, 18:00–22:00 Mar 27 01:00–03:00, 18:00–21:00, 23:00–24:00 Mar 28 00:00–01:00 Mar 29 20:00–24:00 Mar 30 20:00–23:00 Mar 31 03:00–05:00, 16:00–19:00, 22:00–24:00
April
Apr 1 18:00–20:00 Apr 2 02:00–05:00, 19:00–20:00 Apr 3 01:00–03:00 Apr 4 04:00–06:00, 17:00–19:00 Apr 6 19:00–21:00 Apr 7 03:00–04:00, 17:00–20:00 Apr 8 02:00–05:00, 17:00–20:00, 23:00–24:00 Apr 9 03:00–05:00, 18:00–21:00 Apr 10 00:00–02:00, 20:00–23:00 Apr 11 21:00–23:00 Apr 12 19:00–23:00 Apr 13 19:00–21:00 Apr 14 01:00–04:00, 17:00–20:00 Apr 15 04:00–06:00, 18:00–21:00 Apr 16 03:00–06:00, 19:00–24:00 Apr 17 00:00–01:00, 21:00–23:00 Apr 18 04:00–05:00, 18:00–19:00 Apr 19 05:00–08:00, 20:00–23:00 Apr 20 19:00–22:00 Apr 21 04:00–06:00, 19:00–22:00 Apr 22 03:00–06:00, 21:00–24:00 Apr 23 00:00–02:00, 20:00–21:00 Apr 24 02:00–05:00, 19:00–23:00 Apr 25 01:00–02:00, 05:00–06:00, 19:00–20:00 Apr 26 00:00–06:00, 19:00–21:00 Apr 27 19:00–21:00 Apr 28 00:00–02:00, 18:00–21:00 Apr 29 19:00–23:00 Apr 30 03:00–05:00, 19:00–23:00
May
May 1 03:00–06:00, 17:00–19:00, 21:00–24:00 May 2 17:00–21:00 May 3 05:00–07:00 May 4 00:00–07:00, 18:00–21:00 May 5 04:00–07:00, 19:00–21:00, 23:00–24:00 May 6 17:00–19:00 May 7 16:00–19:00 May 8 17:00–19:00 May 9 21:00–24:00 May 12 02:00–05:00, 22:00–24:00 May 13 18:00–20:00 May 14 00:00–04:00, 20:00–22:00 May 17 04:00–06:00 May 18 03:00–05:00, 18:00–22:00 May 19 04:00–07:00, 18:00–21:00 May 20 05:00–07:00, 18:00–20:00 May 21 01:00–05:00, 18:00–22:00 May 22 03:00–05:00, 19:00–22:00 May 23 20:00–21:00 May 24 01:00–03:00 May 25 21:00–24:00 May 26 05:00–06:00, 19:00–20:00 May 27 05:00–06:00, 17:00–20:00, 23:00–24:00 May 28 00:00–01:00, 19:00–20:00, 23:00–24:00 May 29 04:00–06:00, 20:00–23:00 May 30 04:00–06:00 May 31 19:00–21:00, 23:00–24:00
June
Jun 1 00:00–01:00, 04:00–06:00, 18:00–21:00 Jun 2 04:00–07:00, 18:00–20:00 Jun 3 01:00–03:00, 17:00–18:00 Jun 4 20:00–22:00 Jun 5 00:00–04:00, 17:00–20:00 Jun 6 19:00–23:00 Jun 7 07:00–08:00 Jun 8 00:00–06:00 Jun 9 22:00–24:00 Jun 10 03:00–04:00, 18:00–20:00, 23:00–24:00 Jun 11 23:00–24:00 Jun 12 00:00–02:00, 04:00–07:00, 21:00–24:00 Jun 15 04:00–06:00 Jun 16 22:00–24:00 Jun 17 00:00–01:00, 18:00–20:00, 23:00–24:00 Jun 18 00:00–01:00, 18:00–23:00 Jun 19 04:00–06:00, 18:00–21:00 Jun 21 18:00–20:00, 23:00–24:00 Jun 22 00:00–01:00, 18:00–21:00 Jun 23 03:00–05:00, 22:00–24:00 Jun 24 00:00–01:00, 04:00–06:00, 18:00–24:00 Jun 26 18:00–20:00 Jun 29 18:00–21:00 Jun 30 00:00–02:00, 23:00–24:00
July
Jul 1 00:00–01:00, 05:00–06:00, 17:00–20:00 Jul 4 01:00–06:00, 17:00–19:00 Jul 5 05:00–07:00, 19:00–22:00 Jul 8 19:00–22:00 Jul 9 04:00–05:00 Jul 16 05:00–08:00 Jul 17 18:00–21:00 Jul 18 04:00–07:00, 20:00–21:00 Jul 19 02:00–06:00 Jul 20 19:00–20:00, 23:00–24:00 Jul 21 00:00–03:00, 19:00–20:00 Jul 22 05:00–06:00, 19:00–23:00 Jul 24 00:00–01:00, 03:00–04:00, 19:00–20:00, 22:00–24:00 Jul 25 00:00–01:00, 04:00–05:00 Jul 26 01:00–04:00, 19:00–20:00 Jul 27 20:00–21:00 Jul 30 21:00–23:00