Most often in May, 31 days.
Highest follower count seen that year: 55,285.
January
Jan 1 00:00–03:00, 18:00–24:00 Jan 2 00:00–01:00, 07:00–11:00, 23:00–24:00 Jan 3 00:00–08:00, 21:00–24:00 Jan 4 00:00–02:00, 23:00–24:00 Jan 5 00:00–05:00, 07:00–09:00, 20:00–22:00 Jan 6 04:00–08:00 Jan 8 07:00–12:00, 14:00–16:00 Jan 9 04:00–08:00, 18:00–21:00 Jan 10 04:00–07:00, 15:00–18:00 Jan 11 07:00–09:00, 16:00–22:00 Jan 12 10:00–12:00, 20:00–24:00 Jan 13 00:00–01:00, 04:00–06:00, 19:00–24:00 Jan 14 00:00–03:00, 13:00–15:00, 19:00–21:00, 23:00–24:00 Jan 15 09:00–11:00, 14:00–16:00, 19:00–24:00 Jan 16 16:00–17:00 Jan 17 04:00–06:00 Jan 18 22:00–23:00 Jan 19 22:00–24:00 Jan 20 00:00–04:00, 17:00–19:00 Jan 21 02:00–04:00, 09:00–10:00, 18:00–20:00 Jan 22 01:00–04:00, 13:00–14:00, 22:00–24:00 Jan 23 00:00–07:00, 17:00–20:00 Jan 24 01:00–03:00, 05:00–06:00, 18:00–24:00 Jan 25 13:00–14:00, 22:00–24:00 Jan 26 00:00–06:00, 21:00–24:00 Jan 27 01:00–02:00, 07:00–10:00, 19:00–20:00 Jan 28 02:00–05:00 Jan 29 23:00–24:00 Jan 30 00:00–05:00 Jan 31 23:00–24:00
February
Feb 1 00:00–01:00, 03:00–06:00, 14:00–15:00, 23:00–24:00 Feb 2 00:00–07:00, 15:00–16:00, 23:00–24:00 Feb 3 00:00–10:00, 18:00–19:00 Feb 4 03:00–04:00, 21:00–24:00 Feb 5 00:00–01:00, 15:00–17:00 Feb 6 00:00–05:00 Feb 7 01:00–03:00, 11:00–13:00 Feb 8 02:00–04:00, 06:00–07:00, 14:00–16:00 Feb 9 00:00–03:00, 05:00–06:00, 13:00–15:00 Feb 10 00:00–06:00, 15:00–20:00 Feb 11 02:00–05:00, 10:00–13:00, 21:00–23:00 Feb 12 08:00–10:00, 13:00–14:00, 18:00–21:00 Feb 13 08:00–11:00, 13:00–14:00 Feb 14 00:00–02:00, 04:00–05:00, 13:00–17:00, 19:00–20:00 Feb 15 23:00–24:00 Feb 16 00:00–06:00, 15:00–21:00 Feb 24 17:00–23:00 Feb 25 08:00–12:00, 15:00–20:00 Feb 26 10:00–12:00, 17:00–24:00 Feb 27 00:00–01:00, 12:00–17:00, 20:00–24:00 Feb 28 00:00–01:00, 10:00–12:00, 14:00–20:00, 22:00–24:00
March
Mar 1 18:00–23:00 Mar 2 00:00–02:00, 13:00–23:00 Mar 3 16:00–22:00 Mar 4 00:00–03:00, 21:00–22:00 Mar 5 00:00–04:00, 17:00–20:00, 23:00–24:00 Mar 6 00:00–01:00, 11:00–13:00, 16:00–17:00 Mar 7 18:00–24:00 Mar 8 01:00–03:00, 17:00–19:00, 22:00–24:00 Mar 9 05:00–07:00, 21:00–24:00 Mar 10 01:00–03:00, 20:00–23:00 Mar 11 00:00–04:00, 18:00–23:00 Mar 12 00:00–05:00, 23:00–24:00 Mar 13 00:00–07:00, 21:00–23:00 Mar 14 06:00–08:00, 20:00–24:00 Mar 15 00:00–02:00 Mar 16 11:00–13:00, 21:00–23:00 Mar 17 04:00–07:00, 19:00–24:00 Mar 18 00:00–02:00, 23:00–24:00 Mar 19 00:00–01:00, 07:00–11:00, 16:00–18:00 Mar 20 08:00–10:00, 13:00–16:00, 20:00–22:00 Mar 21 08:00–13:00, 17:00–23:00 Mar 23 00:00–03:00, 13:00–14:00, 16:00–17:00, 21:00–24:00 Mar 24 00:00–01:00, 08:00–10:00, 16:00–22:00 Mar 25 09:00–11:00, 18:00–20:00 Mar 26 12:00–15:00, 20:00–23:00 Mar 27 18:00–22:00 Mar 28 15:00–24:00 Mar 29 00:00–02:00, 20:00–24:00 Mar 30 00:00–01:00, 12:00–13:00, 18:00–22:00 Mar 31 13:00–16:00, 18:00–19:00, 21:00–23:00
April
Apr 1 07:00–09:00, 19:00–24:00 Apr 2 00:00–04:00, 20:00–24:00 Apr 3 00:00–02:00 Apr 4 01:00–02:00, 18:00–21:00 Apr 5 16:00–24:00 Apr 6 01:00–04:00, 18:00–22:00 Apr 7 20:00–24:00 Apr 8 00:00–01:00, 15:00–19:00, 22:00–24:00 Apr 9 22:00–24:00 Apr 10 19:00–21:00 Apr 11 13:00–16:00, 18:00–20:00 Apr 12 19:00–24:00 Apr 13 18:00–24:00 Apr 14 00:00–02:00, 18:00–24:00 Apr 15 00:00–03:00, 21:00–24:00 Apr 16 02:00–04:00, 22:00–24:00 Apr 17 00:00–05:00, 17:00–18:00, 20:00–24:00 Apr 18 00:00–03:00 Apr 19 23:00–24:00 Apr 20 00:00–06:00, 08:00–11:00, 13:00–15:00 Apr 21 19:00–22:00 Apr 22 00:00–01:00, 05:00–08:00, 10:00–11:00, 15:00–18:00 Apr 23 05:00–07:00, 22:00–23:00 Apr 24 01:00–02:00, 16:00–21:00 Apr 25 05:00–07:00 Apr 26 00:00–05:00, 17:00–21:00 Apr 27 07:00–08:00, 12:00–14:00, 20:00–22:00 Apr 28 16:00–22:00 Apr 29 11:00–15:00, 18:00–21:00 Apr 30 17:00–23:00
May
May 1 00:00–02:00, 10:00–11:00, 13:00–15:00, 21:00–24:00 May 2 00:00–02:00, 16:00–17:00 May 3 01:00–02:00, 17:00–18:00, 21:00–23:00 May 4 01:00–02:00, 23:00–24:00 May 5 00:00–03:00, 18:00–24:00 May 6 00:00–01:00, 17:00–18:00, 20:00–24:00 May 7 17:00–20:00 May 8 16:00–21:00 May 9 18:00–23:00 May 10 18:00–20:00, 22:00–24:00 May 11 02:00–07:00, 17:00–18:00, 20:00–21:00 May 12 00:00–06:00, 20:00–21:00 May 13 12:00–14:00, 18:00–23:00 May 14 18:00–20:00, 22:00–24:00 May 15 15:00–17:00, 19:00–20:00 May 16 00:00–01:00, 03:00–05:00, 08:00–10:00, 22:00–23:00 May 17 19:00–23:00 May 18 00:00–01:00, 23:00–24:00 May 19 02:00–09:00, 21:00–24:00 May 20 00:00–04:00 May 21 01:00–04:00, 12:00–13:00, 17:00–19:00 May 22 16:00–20:00 May 23 08:00–10:00, 13:00–16:00 May 24 14:00–15:00, 23:00–24:00 May 25 00:00–01:00, 11:00–14:00, 16:00–21:00 May 26 09:00–12:00, 14:00–16:00, 18:00–20:00 May 27 02:00–03:00, 15:00–17:00, 19:00–21:00, 23:00–24:00 May 28 08:00–11:00, 21:00–24:00 May 29 00:00–04:00, 17:00–19:00, 21:00–22:00 May 30 16:00–24:00 May 31 18:00–24:00
June
Jun 1 01:00–02:00, 14:00–23:00 Jun 2 01:00–02:00, 16:00–18:00 Jun 3 02:00–03:00, 20:00–24:00 Jun 4 01:00–02:00 Jun 5 19:00–22:00 Jun 6 06:00–09:00, 18:00–21:00, 23:00–24:00 Jun 7 00:00–01:00, 14:00–24:00 Jun 8 18:00–24:00 Jun 9 18:00–22:00 Jun 10 00:00–02:00, 18:00–23:00 Jun 11 07:00–09:00 Jun 17 09:00–12:00, 21:00–23:00 Jun 19 05:00–06:00, 09:00–13:00, 15:00–17:00 Jun 20 01:00–02:00 Jun 21 01:00–05:00, 14:00–16:00 Jun 22 06:00–10:00, 14:00–21:00 Jun 23 12:00–15:00 Jun 24 04:00–06:00, 08:00–13:00, 15:00–16:00 Jun 25 06:00–08:00, 16:00–22:00 Jun 26 17:00–20:00 Jun 27 14:00–19:00 Jun 28 16:00–21:00 Jun 29 11:00–13:00, 16:00–21:00 Jun 30 18:00–24:00
July
Jul 1 00:00–02:00, 17:00–24:00 Jul 2 00:00–04:00, 18:00–23:00 Jul 3 00:00–05:00, 18:00–24:00 Jul 6 11:00–15:00, 18:00–23:00 Jul 7 18:00–24:00 Jul 8 01:00–03:00, 08:00–11:00, 23:00–24:00 Jul 9 00:00–04:00, 06:00–08:00, 18:00–24:00 Jul 10 00:00–01:00, 21:00–24:00 Jul 11 00:00–04:00, 17:00–23:00 Jul 12 01:00–02:00, 15:00–16:00, 19:00–21:00, 23:00–24:00 Jul 13 00:00–05:00, 19:00–24:00 Jul 14 00:00–02:00, 20:00–24:00 Jul 15 00:00–01:00, 18:00–23:00 Jul 16 05:00–08:00, 21:00–24:00 Jul 17 00:00–02:00, 16:00–17:00, 20:00–21:00 Jul 18 02:00–06:00 Jul 19 01:00–05:00 Jul 20 03:00–07:00, 12:00–14:00, 19:00–23:00 Jul 22 20:00–21:00 Jul 23 18:00–23:00 Jul 24 00:00–01:00, 08:00–10:00, 19:00–23:00 Jul 25 11:00–13:00 Jul 26 15:00–16:00, 19:00–20:00 Jul 27 19:00–21:00