Most often in March, 30 days.
Highest follower count seen that year: 48,723.
January
Jan 2 06:00–11:00 Jan 3 07:00–15:00 Jan 4 11:00–14:00 Jan 5 11:00–16:00 Jan 6 11:00–16:00 Jan 7 07:00–16:00 Jan 8 08:00–15:00 Jan 9 08:00–11:00 Jan 10 07:00–15:00 Jan 11 07:00–15:00 Jan 12 07:00–15:00 Jan 27 06:00–15:00 Jan 28 07:00–16:00 Jan 29 07:00–09:00, 11:00–15:00 Jan 30 07:00–10:00 Jan 31 07:00–15:00
February
Feb 1 07:00–15:00 Feb 2 10:00–15:00 Feb 3 07:00–14:00 Feb 4 08:00–09:00, 11:00–16:00 Feb 5 07:00–08:00, 11:00–16:00 Feb 6 07:00–14:00 Feb 7 07:00–17:00 Feb 8 10:00–20:00 Feb 9 07:00–16:00 Feb 10 11:00–14:00, 16:00–20:00 Feb 11 07:00–16:00, 18:00–19:00 Feb 12 07:00–09:00, 11:00–15:00 Feb 13 07:00–09:00, 11:00–14:00 Feb 14 08:00–16:00, 18:00–20:00 Feb 15 11:00–19:00 Feb 16 08:00–09:00, 11:00–15:00, 17:00–20:00 Feb 17 07:00–15:00, 17:00–19:00 Feb 18 07:00–08:00, 12:00–18:00 Feb 19 07:00–19:00 Feb 20 06:00–09:00 Feb 21 06:00–09:00, 11:00–16:00 Feb 22 07:00–16:00 Feb 23 07:00–16:00 Feb 24 06:00–10:00 Feb 26 06:00–18:00 Feb 27 08:00–14:00 Feb 28 08:00–10:00, 12:00–15:00
March
Mar 1 08:00–17:00 Mar 2 07:00–16:00 Mar 3 07:00–16:00 Mar 4 07:00–15:00, 17:00–20:00 Mar 5 08:00–16:00, 18:00–21:00 Mar 6 08:00–10:00, 12:00–15:00 Mar 7 07:00–18:00 Mar 8 07:00–20:00 Mar 9 07:00–15:00, 17:00–19:00 Mar 10 07:00–20:00 Mar 11 07:00–20:00 Mar 12 07:00–21:00 Mar 13 07:00–16:00 Mar 14 07:00–10:00, 12:00–16:00 Mar 15 07:00–14:00 Mar 16 07:00–20:00 Mar 17 07:00–16:00 Mar 18 07:00–20:00 Mar 19 07:00–16:00 Mar 20 07:00–14:00 Mar 21 07:00–10:00, 12:00–16:00 Mar 23 11:00–18:00 Mar 24 08:00–18:00 Mar 25 08:00–19:00 Mar 26 08:00–16:00 Mar 27 07:00–16:00 Mar 28 07:00–16:00, 18:00–20:00 Mar 29 10:00–16:00 Mar 30 07:00–16:00 Mar 31 08:00–16:00
April
Apr 1 07:00–16:00 Apr 2 06:00–15:00 Apr 3 06:00–16:00 Apr 5 07:00–15:00 Apr 6 07:00–15:00 Apr 7 07:00–19:00 Apr 8 07:00–16:00 Apr 9 07:00–16:00 Apr 10 07:00–16:00 Apr 11 07:00–10:00, 12:00–16:00 Apr 12 07:00–16:00 Apr 13 07:00–15:00 Apr 14 07:00–16:00 Apr 15 08:00–09:00, 11:00–15:00 Apr 16 11:00–14:00 Apr 17 08:00–09:00, 11:00–15:00 Apr 18 07:00–09:00, 11:00–14:00 Apr 19 11:00–13:00 Apr 20 07:00–10:00 Apr 21 08:00–10:00, 12:00–15:00 Apr 22 07:00–16:00 Apr 23 07:00–15:00 Apr 24 08:00–16:00 Apr 26 11:00–16:00 Apr 27 12:00–16:00 Apr 28 11:00–15:00 Apr 29 07:00–15:00 Apr 30 11:00–16:00
May
May 1 07:00–10:00, 12:00–16:00 May 2 07:00–08:00, 11:00–14:00 May 3 08:00–15:00 May 4 11:00–14:00 May 5 07:00–10:00, 12:00–16:00 May 7 07:00–20:00 May 8 07:00–10:00 May 9 07:00–09:00, 11:00–15:00 May 12 07:00–09:00, 12:00–17:00 May 13 07:00–15:00 May 14 11:00–15:00 May 15 07:00–10:00 May 16 11:00–14:00 May 17 07:00–10:00, 12:00–16:00, 18:00–20:00 May 18 07:00–10:00, 12:00–14:00 May 19 08:00–15:00 May 20 11:00–14:00 May 21 07:00–10:00, 12:00–13:00 May 22 08:00–15:00 May 23 12:00–16:00 May 25 11:00–16:00 May 26 07:00–10:00, 12:00–15:00 May 27 08:00–14:00 May 28 07:00–10:00, 12:00–13:00 May 29 07:00–10:00, 12:00–16:00 May 31 07:00–10:00, 12:00–15:00
June
Jun 1 08:00–16:00 Jun 2 12:00–16:00 Jun 3 07:00–10:00, 12:00–15:00 Jun 4 07:00–09:00, 11:00–16:00 Jun 5 12:00–15:00 Jun 6 07:00–09:00, 12:00–14:00 Jun 7 09:00–17:00 Jun 9 07:00–09:00, 12:00–15:00 Jun 10 07:00–11:00 Jun 11 08:00–10:00, 12:00–14:00 Jun 12 08:00–15:00 Jun 13 12:00–16:00 Jun 15 11:00–12:00 Jun 16 11:00–15:00 Jun 17 07:00–14:00 Jun 18 07:00–15:00 Jun 19 11:00–13:00 Jun 22 12:00–16:00 Jun 23 11:00–15:00 Jun 24 07:00–15:00 Jun 25 12:00–16:00 Jun 26 07:00–15:00 Jun 27 07:00–09:00, 11:00–15:00 Jun 28 07:00–09:00, 11:00–15:00 Jun 29 07:00–08:00, 11:00–15:00 Jun 30 08:00–10:00
July
Jul 1 07:00–09:00, 11:00–16:00 Jul 2 07:00–10:00 Jul 3 11:00–16:00 Jul 4 07:00–09:00, 11:00–15:00 Jul 5 09:00–17:00 Jul 6 07:00–10:00 Jul 7 08:00–10:00, 13:00–15:00, 17:00–19:00 Jul 8 07:00–16:00, 18:00–20:00 Jul 9 07:00–10:00, 12:00–19:00 Jul 10 07:00–16:00 Jul 11 07:00–09:00, 11:00–19:00 Jul 12 07:00–09:00, 11:00–20:00 Jul 13 08:00–10:00, 12:00–16:00 Jul 14 08:00–09:00, 11:00–16:00, 18:00–20:00 Jul 15 08:00–09:00, 12:00–16:00 Jul 16 07:00–09:00 Jul 17 11:00–16:00 Jul 19 11:00–15:00, 17:00–20:00 Jul 20 12:00–16:00, 19:00–22:00 Jul 21 06:00–15:00 Jul 23 08:00–10:00, 13:00–23:00 Jul 24 00:00–01:00, 08:00–18:00 Jul 25 08:00–09:00, 12:00–15:00, 17:00–20:00 Jul 26 08:00–10:00, 12:00–16:00, 17:00–20:00 Jul 27 12:00–13:00, 14:00–15:00