Most often in November, 27 days.
Highest follower count seen that year: 14,653.
January
Jan 1 23:00–24:00 Jan 2 07:00–08:00, 19:00–20:00 Jan 3 02:00–03:00 Jan 5 05:00–06:00, 22:00–23:00 Jan 6 20:00–22:00 Jan 7 21:00–22:00 Jan 8 18:00–20:00, 22:00–23:00 Jan 11 20:00–21:00 Jan 22 22:00–23:00 Jan 23 21:00–22:00 Jan 29 18:00–19:00 Jan 30 18:00–20:00 Jan 31 02:00–04:00
February
Feb 3 17:00–18:00 Feb 9 00:00–01:00 Feb 11 16:00–18:00 Feb 14 18:00–20:00 Feb 16 19:00–21:00 Feb 17 19:00–21:00
March
Mar 3 17:00–18:00 Mar 7 20:00–22:00 Mar 10 19:00–20:00 Mar 15 15:00–16:00 Mar 16 18:00–20:00 Mar 19 15:00–17:00 Mar 20 18:00–19:00 Mar 21 22:00–24:00 Mar 24 17:00–20:00 Mar 27 21:00–23:00 Mar 28 19:00–21:00 Mar 30 00:00–02:00 Mar 31 18:00–22:00
April
Apr 7 19:00–20:00 Apr 8 21:00–23:00 Apr 10 22:00–23:00 Apr 14 15:00–16:00 Apr 15 17:00–18:00 Apr 16 16:00–17:00 Apr 17 17:00–18:00 Apr 24 17:00–18:00 Apr 26 15:00–17:00 Apr 28 19:00–20:00 Apr 29 17:00–19:00 Apr 30 20:00–21:00
May
May 2 17:00–18:00 May 4 17:00–18:00 May 10 19:00–21:00 May 17 17:00–18:00 May 20 22:00–23:00 May 21 18:00–21:00 May 22 14:00–15:00 May 26 18:00–19:00 May 27 02:00–05:00, 19:00–22:00 May 29 17:00–20:00 May 31 18:00–20:00
June
Jun 1 20:00–21:00 Jun 2 08:00–12:00, 15:00–17:00 Jun 3 13:00–17:00 Jun 4 00:00–01:00, 15:00–21:00 Jun 5 16:00–18:00, 21:00–22:00 Jun 6 21:00–22:00 Jun 7 00:00–02:00, 13:00–15:00, 17:00–19:00 Jun 8 00:00–01:00, 21:00–23:00 Jun 9 13:00–16:00, 21:00–22:00 Jun 10 02:00–03:00, 11:00–12:00 Jun 11 15:00–16:00 Jun 12 14:00–15:00, 21:00–24:00 Jun 13 20:00–21:00 Jun 15 17:00–19:00 Jun 16 16:00–17:00, 21:00–22:00 Jun 17 18:00–19:00, 21:00–23:00 Jun 19 21:00–23:00 Jun 20 16:00–17:00 Jun 22 22:00–23:00 Jun 25 16:00–17:00 Jun 26 21:00–23:00 Jun 27 14:00–16:00, 23:00–24:00 Jun 28 19:00–23:00 Jun 30 15:00–18:00
July
Jul 1 19:00–23:00 Jul 2 13:00–16:00 Jul 3 01:00–03:00, 16:00–18:00 Jul 4 21:00–22:00 Jul 5 15:00–17:00 Jul 9 19:00–21:00 Jul 10 12:00–13:00 Jul 12 15:00–17:00 Jul 13 18:00–19:00 Jul 14 20:00–22:00 Jul 16 15:00–18:00 Jul 21 20:00–24:00 Jul 23 11:00–13:00, 20:00–22:00 Jul 24 11:00–12:00, 15:00–24:00 Jul 25 00:00–02:00, 21:00–23:00 Jul 26 18:00–19:00, 23:00–24:00 Jul 27 00:00–01:00, 18:00–21:00 Jul 29 19:00–21:00 Jul 30 17:00–18:00, 22:00–24:00 Jul 31 17:00–20:00
August
Aug 1 18:00–21:00 Aug 2 16:00–17:00, 23:00–24:00 Aug 3 16:00–18:00 Aug 4 18:00–20:00 Aug 5 00:00–01:00, 17:00–18:00 Aug 6 00:00–02:00 Aug 7 10:00–12:00, 18:00–20:00 Aug 9 16:00–18:00, 20:00–24:00 Aug 10 00:00–01:00, 17:00–19:00, 21:00–22:00 Aug 11 15:00–19:00, 21:00–22:00 Aug 12 14:00–18:00, 20:00–22:00 Aug 13 14:00–24:00 Aug 14 01:00–02:00 Aug 17 19:00–21:00 Aug 18 22:00–23:00 Aug 19 16:00–19:00 Aug 20 14:00–17:00 Aug 21 18:00–21:00 Aug 22 03:00–05:00, 22:00–24:00 Aug 23 20:00–22:00 Aug 24 00:00–02:00, 19:00–20:00 Aug 29 01:00–03:00, 16:00–18:00 Aug 30 04:00–05:00 Aug 31 18:00–22:00
September
Sep 2 01:00–03:00, 21:00–22:00 Sep 4 15:00–19:00 Sep 6 17:00–20:00 Sep 8 21:00–24:00 Sep 9 00:00–02:00 Sep 16 18:00–20:00 Sep 19 00:00–04:00 Sep 20 01:00–03:00, 05:00–06:00, 19:00–22:00 Sep 21 01:00–03:00, 23:00–24:00 Sep 22 00:00–01:00, 20:00–22:00 Sep 23 18:00–24:00 Sep 24 01:00–05:00, 15:00–24:00 Sep 25 17:00–20:00 Sep 26 18:00–19:00 Sep 28 16:00–20:00 Sep 29 01:00–05:00, 20:00–24:00 Sep 30 00:00–01:00, 16:00–18:00, 23:00–24:00
October
Oct 1 00:00–02:00, 21:00–24:00 Oct 2 15:00–18:00, 22:00–24:00 Oct 3 00:00–02:00, 17:00–18:00, 22:00–24:00 Oct 4 00:00–01:00, 17:00–20:00, 22:00–24:00 Oct 5 00:00–01:00, 22:00–24:00 Oct 6 19:00–21:00 Oct 8 21:00–23:00 Oct 9 17:00–18:00, 23:00–24:00 Oct 10 00:00–02:00, 17:00–20:00 Oct 11 00:00–02:00, 16:00–19:00, 22:00–23:00 Oct 14 22:00–24:00 Oct 16 16:00–18:00 Oct 17 00:00–01:00 Oct 22 18:00–19:00, 22:00–24:00 Oct 24 16:00–18:00 Oct 25 18:00–20:00 Oct 26 01:00–05:00, 19:00–21:00 Oct 27 01:00–03:00 Oct 28 17:00–18:00, 23:00–24:00 Oct 29 00:00–02:00, 20:00–22:00 Oct 30 11:00–14:00
November
Nov 1 17:00–20:00 Nov 2 02:00–04:00, 19:00–21:00 Nov 3 21:00–24:00 Nov 4 02:00–05:00, 22:00–24:00 Nov 5 00:00–01:00, 20:00–23:00 Nov 6 04:00–10:00, 19:00–21:00, 23:00–24:00 Nov 7 00:00–01:00, 19:00–21:00 Nov 8 02:00–06:00, 19:00–22:00 Nov 9 04:00–06:00 Nov 10 19:00–22:00 Nov 13 16:00–17:00 Nov 15 20:00–22:00 Nov 16 00:00–02:00, 19:00–21:00, 23:00–24:00 Nov 17 00:00–01:00 Nov 18 19:00–22:00 Nov 19 01:00–03:00, 22:00–24:00 Nov 20 00:00–02:00, 21:00–23:00 Nov 21 03:00–05:00, 20:00–22:00 Nov 22 02:00–05:00, 19:00–21:00, 23:00–24:00 Nov 23 00:00–01:00 Nov 24 17:00–19:00 Nov 25 19:00–22:00 Nov 26 01:00–02:00, 19:00–21:00 Nov 27 19:00–21:00 Nov 28 18:00–21:00 Nov 29 02:00–04:00, 19:00–21:00 Nov 30 02:00–05:00, 19:00–22:00
December
Dec 1 01:00–03:00, 19:00–21:00 Dec 2 02:00–05:00 Dec 3 19:00–21:00 Dec 4 01:00–02:00, 17:00–21:00 Dec 5 02:00–04:00 Dec 6 00:00–03:00, 19:00–21:00 Dec 7 01:00–04:00, 20:00–22:00 Dec 8 01:00–03:00, 17:00–18:00 Dec 9 01:00–03:00, 20:00–22:00 Dec 10 20:00–21:00 Dec 11 15:00–16:00 Dec 12 18:00–21:00 Dec 13 01:00–02:00, 19:00–22:00 Dec 14 02:00–04:00, 19:00–20:00 Dec 15 01:00–03:00, 20:00–22:00 Dec 16 12:00–13:00 Dec 17 21:00–23:00 Dec 19 19:00–20:00 Dec 20 19:00–21:00 Dec 21 19:00–22:00 Dec 22 01:00–02:00 Dec 23 19:00–21:00 Dec 27 23:00–24:00 Dec 28 19:00–21:00 Dec 29 01:00–02:00 Dec 30 01:00–03:00, 19:00–21:00 Dec 31 18:00–20:00