Most often in December, 22 days.
Highest follower count seen that year: 64,058.
January
Jan 3 13:00–17:00 Jan 4 08:00–13:00, 16:00–18:00 Jan 5 07:00–11:00, 19:00–23:00 Jan 6 14:00–17:00, 20:00–22:00 Jan 7 06:00–11:00, 14:00–15:00, 21:00–23:00 Jan 11 04:00–10:00, 16:00–18:00, 20:00–21:00 Jan 12 16:00–18:00 Jan 13 14:00–17:00 Jan 16 09:00–12:00, 14:00–17:00 Jan 17 12:00–13:00, 19:00–21:00 Jan 18 15:00–17:00 Jan 19 05:00–09:00, 14:00–18:00 Jan 20 06:00–10:00, 15:00–18:00 Jan 21 06:00–11:00 Jan 24 15:00–18:00 Jan 25 05:00–10:00, 15:00–18:00 Jan 26 06:00–11:00, 16:00–19:00 Jan 27 06:00–11:00
February
Feb 1 05:00–10:00, 14:00–17:00 Feb 2 06:00–11:00, 15:00–18:00 Feb 3 05:00–10:00, 16:00–18:00 Feb 4 05:00–11:00 Feb 6 15:00–18:00 Feb 7 05:00–09:00, 15:00–17:00 Feb 10 14:00–16:00 Feb 11 08:00–11:00 Feb 13 05:00–09:00, 15:00–16:00 Feb 14 05:00–09:00 Feb 16 04:00–10:00, 16:00–18:00 Feb 17 10:00–13:00 Feb 23 05:00–10:00 Feb 24 15:00–17:00 Feb 25 05:00–10:00 Feb 27 05:00–10:00, 20:00–23:00 Feb 28 05:00–09:00, 22:00–24:00
March
Mar 1 00:00–01:00, 11:00–13:00 Mar 7 10:00–12:00 Mar 8 05:00–09:00 Mar 12 06:00–09:00 Mar 13 12:00–15:00, 21:00–24:00 Mar 17 04:00–05:00 Mar 20 22:00–24:00 Mar 21 00:00–01:00, 13:00–16:00 Mar 22 20:00–24:00 Mar 23 15:00–18:00, 20:00–23:00 Mar 24 14:00–16:00, 22:00–24:00
April
Apr 1 19:00–22:00 Apr 2 05:00–07:00 Apr 3 04:00–06:00, 08:00–10:00 Apr 5 03:00–11:00 Apr 6 04:00–08:00 Apr 7 05:00–09:00, 12:00–13:00 Apr 11 04:00–09:00 Apr 12 05:00–09:00, 15:00–17:00 Apr 13 18:00–22:00 Apr 15 04:00–08:00 Apr 21 05:00–09:00 Apr 22 21:00–23:00 Apr 23 07:00–09:00 Apr 24 15:00–17:00 Apr 25 04:00–09:00 Apr 26 04:00–08:00, 15:00–17:00 Apr 28 06:00–07:00 Apr 29 11:00–15:00 Apr 30 15:00–17:00
May
May 1 10:00–15:00 May 6 10:00–13:00, 15:00–16:00 May 8 04:00–07:00 May 9 09:00–12:00 May 10 00:00–02:00, 14:00–16:00 May 12 11:00–17:00 May 13 13:00–15:00 May 16 14:00–17:00 May 18 07:00–09:00 May 21 15:00–17:00, 20:00–23:00 May 23 08:00–09:00, 22:00–24:00 May 25 05:00–08:00 May 28 14:00–16:00 May 29 14:00–17:00
June
Jun 3 14:00–16:00 Jun 4 14:00–17:00 Jun 7 15:00–17:00 Jun 8 06:00–09:00, 22:00–24:00 Jun 9 00:00–01:00 Jun 11 15:00–17:00 Jun 18 11:00–14:00
July
Jul 3 05:00–08:00 Jul 5 15:00–17:00 Jul 6 05:00–06:00 Jul 7 14:00–17:00 Jul 9 14:00–17:00 Jul 11 22:00–24:00 Jul 14 13:00–16:00 Jul 20 14:00–16:00 Jul 21 08:00–09:00 Jul 24 04:00–07:00 Jul 25 07:00–15:00 Jul 27 04:00–06:00 Jul 28 13:00–15:00
August
Aug 25 16:00–17:00 Aug 26 08:00–10:00, 13:00–17:00 Aug 31 16:00–17:00
September
Sep 4 10:00–15:00 Sep 10 14:00–16:00 Sep 13 14:00–17:00 Sep 14 05:00–08:00, 14:00–16:00 Sep 22 05:00–09:00 Sep 24 06:00–07:00 Sep 25 10:00–11:00, 13:00–16:00 Sep 26 05:00–08:00 Sep 27 07:00–09:00 Sep 28 04:00–09:00 Sep 29 04:00–08:00 Sep 30 04:00–06:00, 18:00–20:00
October
Oct 1 05:00–07:00, 12:00–15:00 Oct 3 14:00–17:00 Oct 4 07:00–10:00, 13:00–15:00 Oct 5 06:00–09:00 Oct 6 05:00–08:00 Oct 7 04:00–08:00 Oct 9 12:00–15:00 Oct 15 03:00–08:00 Oct 18 07:00–12:00 Oct 23 14:00–17:00 Oct 24 07:00–10:00, 14:00–17:00 Oct 25 07:00–09:00, 12:00–13:00, 16:00–18:00 Oct 26 05:00–09:00 Oct 27 05:00–10:00, 16:00–18:00 Oct 28 05:00–10:00, 16:00–18:00 Oct 29 06:00–08:00 Oct 30 06:00–09:00
November
Nov 3 15:00–18:00 Nov 4 05:00–10:00 Nov 6 05:00–09:00, 16:00–18:00 Nov 7 06:00–10:00, 15:00–19:00 Nov 8 06:00–10:00 Nov 12 18:00–20:00 Nov 13 08:00–10:00, 14:00–16:00 Nov 14 08:00–10:00 Nov 15 14:00–18:00 Nov 16 12:00–15:00 Nov 17 07:00–09:00 Nov 18 05:00–08:00 Nov 19 07:00–08:00, 16:00–19:00 Nov 20 06:00–08:00, 16:00–17:00 Nov 25 05:00–09:00 Nov 26 08:00–09:00, 13:00–15:00 Nov 27 06:00–09:00, 13:00–14:00 Nov 28 05:00–09:00, 17:00–18:00 Nov 29 06:00–10:00 Nov 30 06:00–10:00, 17:00–18:00
December
Dec 1 05:00–07:00, 15:00–17:00 Dec 2 06:00–09:00 Dec 3 03:00–09:00, 17:00–18:00 Dec 7 10:00–14:00, 16:00–18:00 Dec 8 08:00–10:00, 17:00–18:00 Dec 9 06:00–09:00 Dec 10 17:00–18:00 Dec 11 05:00–09:00 Dec 12 06:00–09:00 Dec 13 07:00–09:00, 15:00–17:00 Dec 14 05:00–10:00 Dec 15 06:00–10:00, 18:00–20:00 Dec 16 06:00–10:00 Dec 17 06:00–09:00 Dec 21 17:00–20:00 Dec 22 08:00–09:00 Dec 23 09:00–12:00 Dec 24 05:00–10:00, 18:00–21:00 Dec 25 05:00–11:00 Dec 26 05:00–10:00, 18:00–19:00 Dec 27 07:00–10:00 Dec 29 06:00–10:00