Most often in March, 27 days.
Highest follower count seen that year: 75,095.
January
Jan 4 01:00–08:00 Jan 5 01:00–15:00 Jan 6 01:00–16:00 Jan 7 01:00–08:00 Jan 8 01:00–08:00, 10:00–15:00 Jan 9 01:00–08:00 Jan 10 01:00–08:00, 10:00–16:00 Jan 11 01:00–12:00 Jan 12 01:00–12:00 Jan 13 01:00–12:00 Jan 14 01:00–12:00 Jan 15 01:00–08:00 Jan 18 01:00–09:00 Jan 19 00:00–09:00 Jan 20 01:00–15:00 Jan 21 01:00–09:00 Jan 22 01:00–15:00 Jan 23 01:00–08:00 Jan 24 01:00–14:00 Jan 25 01:00–09:00, 11:00–16:00 Jan 26 01:00–09:00 Jan 27 01:00–08:00 Jan 28 01:00–14:00 Jan 29 00:00–08:00 Jan 30 02:00–13:00 Jan 31 01:00–08:00
February
Feb 4 01:00–04:00, 06:00–07:00 Feb 5 00:00–08:00, 10:00–14:00 Feb 6 01:00–08:00, 10:00–14:00 Feb 7 01:00–19:00 Feb 8 00:00–12:00 Feb 9 00:00–08:00 Feb 10 00:00–08:00 Feb 11 00:00–08:00 Feb 12 01:00–13:00 Feb 13 01:00–09:00 Feb 14 01:00–07:00 Feb 15 02:00–05:00 Feb 16 01:00–16:00 Feb 17 01:00–16:00 Feb 18 01:00–14:00 Feb 19 01:00–08:00 Feb 20 01:00–08:00, 10:00–11:00 Feb 21 01:00–16:00 Feb 22 01:00–08:00, 10:00–16:00 Feb 23 01:00–08:00, 11:00–15:00 Feb 24 00:00–08:00, 10:00–14:00 Feb 25 01:00–08:00, 10:00–14:00 Feb 26 01:00–08:00, 10:00–18:00 Feb 27 00:00–08:00 Feb 28 01:00–08:00
March
Mar 3 02:00–08:00 Mar 4 01:00–08:00 Mar 5 01:00–09:00, 11:00–14:00 Mar 6 01:00–08:00, 10:00–12:00 Mar 7 01:00–04:00, 06:00–16:00 Mar 8 01:00–09:00 Mar 9 01:00–08:00 Mar 10 01:00–10:00 Mar 11 01:00–08:00 Mar 12 01:00–08:00 Mar 13 02:00–15:00 Mar 14 01:00–04:00, 06:00–10:00 Mar 15 01:00–08:00, 10:00–15:00 Mar 18 01:00–08:00 Mar 19 01:00–08:00, 10:00–16:00 Mar 20 01:00–16:00 Mar 21 01:00–08:00 Mar 22 01:00–08:00, 10:00–16:00 Mar 23 01:00–04:00, 06:00–08:00, 11:00–13:00 Mar 24 01:00–08:00, 12:00–16:00 Mar 25 01:00–04:00, 12:00–17:00 Mar 26 01:00–08:00 Mar 27 01:00–08:00, 10:00–16:00 Mar 28 01:00–12:00 Mar 29 01:00–08:00, 11:00–17:00 Mar 30 01:00–08:00, 12:00–16:00 Mar 31 01:00–07:00
April
Apr 11 03:00–14:00 Apr 12 01:00–08:00 Apr 13 00:00–08:00 Apr 14 01:00–07:00, 11:00–14:00 Apr 15 01:00–08:00 Apr 16 00:00–08:00, 11:00–16:00 Apr 17 01:00–08:00 Apr 18 01:00–09:00, 11:00–15:00 Apr 19 01:00–08:00 Apr 20 01:00–08:00, 11:00–15:00 Apr 21 01:00–08:00 Apr 22 01:00–04:00, 06:00–08:00, 11:00–15:00 Apr 23 01:00–08:00 Apr 24 01:00–08:00, 11:00–15:00 Apr 25 01:00–04:00, 06:00–08:00 Apr 26 01:00–04:00, 06:00–08:00, 11:00–15:00 Apr 27 01:00–09:00 Apr 28 01:00–07:00, 11:00–15:00 Apr 29 00:00–08:00, 10:00–14:00 Apr 30 01:00–07:00
May
May 3 01:00–04:00, 06:00–08:00, 12:00–15:00 May 4 01:00–08:00, 12:00–15:00 May 5 01:00–04:00, 07:00–08:00 May 6 01:00–08:00, 11:00–15:00 May 7 01:00–08:00 May 8 01:00–10:00, 12:00–14:00 May 9 02:00–04:00, 06:00–08:00 May 10 01:00–09:00, 11:00–14:00 May 11 01:00–08:00 May 12 01:00–08:00, 11:00–14:00 May 13 01:00–08:00 May 14 01:00–08:00, 10:00–14:00 May 15 01:00–08:00 May 20 01:00–08:00, 11:00–15:00 May 21 01:00–08:00 May 22 01:00–08:00, 11:00–14:00 May 23 00:00–08:00, 12:00–14:00 May 24 01:00–08:00 May 25 01:00–08:00, 11:00–14:00 May 26 01:00–04:00, 06:00–08:00 May 27 00:00–08:00, 11:00–14:00 May 28 01:00–08:00 May 29 01:00–04:00, 06:00–08:00
June
Jun 5 01:00–04:00, 06:00–08:00 Jun 6 01:00–04:00, 06:00–08:00, 11:00–15:00 Jun 7 02:00–08:00 Jun 8 02:00–15:00 Jun 9 01:00–10:00 Jun 10 01:00–04:00, 06:00–08:00, 11:00–14:00 Jun 11 01:00–12:00 Jun 12 01:00–05:00 Jun 13 02:00–04:00, 06:00–08:00, 12:00–14:00 Jun 15 01:00–07:00 Jun 17 09:00–11:00 Jun 18 01:00–08:00, 11:00–14:00 Jun 19 01:00–08:00 Jun 20 02:00–08:00, 10:00–14:00 Jun 21 01:00–08:00, 10:00–16:00 Jun 22 01:00–08:00 Jun 23 05:00–08:00 Jun 24 01:00–08:00, 11:00–14:00 Jun 25 00:00–08:00 Jun 26 01:00–09:00, 11:00–14:00 Jun 27 01:00–08:00 Jun 28 01:00–08:00 Jun 29 01:00–04:00, 06:00–08:00, 10:00–15:00 Jun 30 01:00–08:00
July
Jul 1 16:00–21:00 Jul 4 01:00–14:00 Jul 5 01:00–08:00, 11:00–14:00 Jul 6 00:00–14:00 Jul 7 00:00–08:00 Jul 8 01:00–14:00 Jul 9 01:00–08:00 Jul 10 01:00–08:00, 11:00–15:00 Jul 11 01:00–09:00 Jul 12 00:00–09:00, 11:00–14:00 Jul 13 01:00–09:00 Jul 14 00:00–08:00, 11:00–14:00 Jul 15 01:00–04:00, 06:00–08:00 Jul 19 01:00–08:00 Jul 20 01:00–11:00 Jul 21 02:00–08:00 Jul 22 01:00–08:00 Jul 23 02:00–08:00, 12:00–15:00 Jul 24 02:00–04:00, 06:00–08:00 Jul 25 02:00–09:00, 11:00–14:00 Jul 26 01:00–04:00, 06:00–09:00, 10:00–11:00 Jul 27 01:00–05:00, 06:00–09:00, 12:00–15:00