Most often in December, 25 days.
Highest follower count seen that year: 36,066.
January
Jan 4 08:00–09:00 Jan 5 12:00–13:00 Jan 6 05:00–06:00 Jan 8 05:00–08:00 Jan 9 08:00–10:00 Jan 10 09:00–11:00 Jan 11 07:00–11:00 Jan 13 05:00–07:00 Jan 14 14:00–17:00 Jan 16 19:00–22:00 Jan 18 13:00–15:00 Jan 19 13:00–16:00 Jan 20 13:00–18:00 Jan 21 08:00–11:00 Jan 22 12:00–15:00 Jan 24 08:00–10:00 Jan 25 08:00–11:00 Jan 26 19:00–20:00 Jan 27 05:00–07:00 Jan 28 09:00–11:00 Jan 29 05:00–07:00, 13:00–16:00
February
Feb 1 13:00–18:00 Feb 2 09:00–11:00 Feb 3 15:00–17:00 Feb 4 06:00–07:00 Feb 6 14:00–15:00 Feb 8 14:00–17:00 Feb 9 08:00–10:00 Feb 10 14:00–16:00 Feb 11 09:00–11:00, 13:00–17:00 Feb 12 14:00–17:00 Feb 13 14:00–18:00 Feb 14 07:00–10:00, 19:00–22:00 Feb 16 13:00–17:00 Feb 17 06:00–08:00 Feb 19 14:00–18:00 Feb 21 14:00–16:00 Feb 22 08:00–11:00 Feb 23 06:00–08:00 Feb 24 08:00–11:00 Feb 25 15:00–18:00 Feb 26 08:00–11:00, 14:00–18:00 Feb 28 08:00–11:00
March
Mar 3 12:00–17:00 Mar 4 08:00–10:00 Mar 6 08:00–10:00, 14:00–18:00 Mar 7 14:00–15:00 Mar 9 13:00–18:00 Mar 10 14:00–17:00 Mar 11 08:00–10:00 Mar 12 15:00–18:00 Mar 13 05:00–07:00 Mar 14 08:00–11:00, 15:00–16:00 Mar 15 08:00–10:00 Mar 17 13:00–15:00 Mar 18 08:00–11:00, 13:00–18:00 Mar 20 08:00–11:00, 15:00–18:00 Mar 21 15:00–18:00 Mar 22 15:00–18:00 Mar 23 14:00–18:00 Mar 24 15:00–17:00 Mar 26 13:00–17:00 Mar 27 14:00–17:00 Mar 28 15:00–18:00 Mar 29 16:00–18:00 Mar 30 15:00–18:00
April
Apr 1 14:00–18:00 Apr 3 14:00–16:00 Apr 6 09:00–11:00 Apr 7 15:00–18:00 Apr 8 13:00–18:00 Apr 9 08:00–11:00, 15:00–18:00 Apr 10 12:00–17:00 Apr 11 13:00–18:00 Apr 12 14:00–17:00 Apr 13 15:00–17:00 Apr 14 15:00–17:00 Apr 15 15:00–17:00 Apr 16 15:00–17:00 Apr 17 05:00–06:00, 17:00–18:00 Apr 21 08:00–11:00 Apr 22 14:00–16:00 Apr 23 08:00–10:00, 14:00–18:00 Apr 25 14:00–17:00 Apr 26 13:00–18:00 Apr 27 14:00–18:00, 20:00–22:00 Apr 29 13:00–17:00, 20:00–22:00 Apr 30 14:00–18:00
May
May 1 14:00–18:00 May 2 15:00–16:00 May 3 14:00–17:00 May 4 14:00–16:00 May 5 15:00–16:00 May 6 15:00–17:00 May 7 14:00–16:00 May 9 15:00–17:00 May 10 13:00–16:00 May 12 13:00–17:00 May 13 05:00–07:00 May 14 05:00–06:00 May 17 14:00–17:00 May 18 15:00–18:00 May 19 14:00–17:00 May 21 06:00–07:00, 14:00–16:00 May 22 15:00–18:00 May 23 14:00–18:00 May 24 08:00–11:00, 14:00–16:00 May 25 14:00–17:00 May 27 14:00–17:00 May 28 05:00–06:00, 15:00–16:00 May 29 15:00–17:00 May 30 15:00–17:00
June
Jun 1 09:00–11:00, 13:00–15:00 Jun 2 08:00–11:00, 16:00–19:00 Jun 3 12:00–15:00 Jun 4 08:00–11:00, 13:00–15:00 Jun 6 13:00–16:00 Jun 8 08:00–11:00 Jun 10 15:00–17:00 Jun 11 15:00–18:00 Jun 12 20:00–21:00 Jun 13 15:00–16:00 Jun 14 15:00–18:00 Jun 15 16:00–18:00 Jun 16 05:00–06:00 Jun 17 15:00–18:00 Jun 18 09:00–11:00 Jun 20 15:00–17:00 Jun 21 07:00–11:00, 13:00–18:00 Jun 24 13:00–16:00 Jun 25 08:00–16:00 Jun 26 14:00–18:00 Jun 27 15:00–18:00 Jun 28 09:00–11:00 Jun 30 15:00–17:00
July
Jul 2 09:00–11:00 Jul 5 15:00–18:00, 20:00–22:00 Jul 6 15:00–18:00 Jul 7 14:00–17:00 Jul 8 05:00–06:00 Jul 9 14:00–18:00 Jul 10 13:00–17:00 Jul 11 08:00–15:00 Jul 12 08:00–11:00 Jul 13 19:00–21:00 Jul 14 13:00–17:00 Jul 15 13:00–15:00, 20:00–23:00 Jul 16 05:00–06:00, 15:00–17:00 Jul 17 13:00–14:00 Jul 19 19:00–21:00 Jul 20 13:00–15:00 Jul 21 14:00–17:00 Jul 22 14:00–16:00 Jul 23 13:00–17:00 Jul 25 14:00–18:00 Jul 26 13:00–17:00 Jul 27 14:00–18:00 Jul 28 14:00–16:00 Jul 29 08:00–11:00
August
Aug 1 14:00–16:00 Aug 2 15:00–18:00, 22:00–24:00 Aug 3 00:00–01:00 Aug 4 14:00–17:00 Aug 5 15:00–18:00 Aug 6 14:00–18:00 Aug 7 13:00–16:00 Aug 8 14:00–18:00 Aug 10 13:00–17:00 Aug 11 15:00–17:00 Aug 12 12:00–17:00, 19:00–22:00 Aug 13 08:00–16:00 Aug 14 13:00–17:00, 19:00–21:00 Aug 16 13:00–17:00 Aug 17 15:00–18:00 Aug 18 14:00–17:00 Aug 19 13:00–18:00 Aug 20 14:00–16:00 Aug 21 14:00–17:00 Aug 22 14:00–18:00 Aug 23 08:00–11:00, 19:00–22:00 Aug 24 08:00–11:00
September
Sep 1 07:00–10:00, 20:00–21:00 Sep 3 15:00–17:00 Sep 4 15:00–18:00 Sep 5 08:00–10:00 Sep 9 13:00–17:00 Sep 10 08:00–11:00, 13:00–17:00 Sep 11 13:00–16:00 Sep 12 13:00–14:00 Sep 13 07:00–10:00 Sep 14 14:00–15:00 Sep 15 14:00–17:00 Sep 16 14:00–18:00 Sep 17 14:00–18:00 Sep 18 13:00–17:00 Sep 19 14:00–17:00 Sep 20 07:00–11:00 Sep 22 16:00–18:00 Sep 23 13:00–15:00 Sep 24 14:00–18:00 Sep 25 15:00–18:00 Sep 26 08:00–10:00, 15:00–16:00 Sep 27 14:00–17:00 Sep 28 19:00–22:00 Sep 29 14:00–17:00 Sep 30 13:00–17:00, 19:00–21:00
October
Oct 1 15:00–16:00 Oct 5 13:00–16:00 Oct 6 08:00–10:00 Oct 7 10:00–12:00 Oct 8 08:00–11:00, 13:00–14:00 Oct 9 14:00–18:00 Oct 10 09:00–17:00 Oct 11 13:00–17:00 Oct 12 08:00–11:00, 13:00–16:00 Oct 13 14:00–17:00 Oct 14 14:00–17:00 Oct 15 08:00–10:00, 15:00–17:00 Oct 16 08:00–11:00 Oct 17 06:00–11:00, 15:00–16:00 Oct 19 13:00–15:00 Oct 21 13:00–15:00 Oct 22 15:00–16:00 Oct 23 12:00–16:00 Oct 24 08:00–11:00, 15:00–17:00 Oct 26 14:00–17:00 Oct 27 16:00–17:00 Oct 28 09:00–11:00, 14:00–17:00 Oct 29 13:00–15:00 Oct 30 14:00–17:00 Oct 31 14:00–20:00
November
Nov 1 07:00–09:00 Nov 2 14:00–17:00 Nov 3 14:00–18:00 Nov 5 08:00–11:00, 13:00–16:00 Nov 7 08:00–11:00 Nov 9 14:00–17:00 Nov 10 14:00–18:00 Nov 11 15:00–17:00 Nov 12 14:00–17:00 Nov 13 14:00–17:00 Nov 14 14:00–16:00 Nov 15 05:00–07:00, 15:00–16:00 Nov 16 15:00–16:00 Nov 17 15:00–18:00 Nov 19 14:00–16:00 Nov 21 14:00–17:00 Nov 25 13:00–15:00, 20:00–22:00 Nov 26 14:00–18:00 Nov 27 08:00–11:00, 20:00–21:00 Nov 28 14:00–17:00, 20:00–22:00 Nov 29 07:00–11:00, 14:00–17:00 Nov 30 08:00–10:00, 13:00–16:00
December
Dec 2 14:00–20:00 Dec 3 09:00–11:00, 13:00–16:00 Dec 4 14:00–18:00 Dec 5 13:00–18:00 Dec 7 14:00–16:00 Dec 8 08:00–10:00 Dec 9 08:00–11:00, 15:00–17:00 Dec 10 08:00–12:00 Dec 11 08:00–11:00, 20:00–22:00 Dec 12 07:00–10:00, 12:00–15:00, 20:00–23:00 Dec 14 14:00–16:00, 20:00–23:00 Dec 15 09:00–11:00, 13:00–17:00 Dec 17 15:00–17:00 Dec 18 13:00–17:00 Dec 19 08:00–11:00, 20:00–21:00 Dec 20 19:00–20:00 Dec 21 08:00–11:00, 15:00–17:00 Dec 22 15:00–18:00 Dec 23 15:00–16:00 Dec 24 14:00–17:00 Dec 25 15:00–17:00 Dec 26 14:00–18:00 Dec 27 14:00–16:00 Dec 28 14:00–18:00 Dec 29 08:00–10:00