Most often in October, 25 days.
Highest follower count seen that year: 40,904.
January
Jan 2 10:00–14:00, 19:00–20:00 Jan 3 08:00–13:00 Jan 4 09:00–15:00 Jan 5 16:00–18:00 Jan 6 11:00–12:00 Jan 8 09:00–13:00 Jan 9 20:00–24:00 Jan 10 08:00–12:00, 20:00–22:00 Jan 14 09:00–14:00 Jan 15 07:00–13:00 Jan 16 07:00–12:00, 20:00–23:00 Jan 17 08:00–12:00 Jan 18 12:00–18:00 Jan 20 09:00–12:00 Jan 21 07:00–11:00 Jan 22 07:00–09:00 Jan 23 08:00–09:00 Jan 24 08:00–09:00 Jan 25 19:00–20:00 Jan 26 09:00–13:00 Jan 27 07:00–12:00 Jan 28 08:00–11:00 Jan 29 07:00–08:00, 11:00–13:00 Jan 30 09:00–12:00 Jan 31 08:00–13:00
February
Feb 1 11:00–14:00 Feb 2 00:00–02:00 Feb 3 19:00–23:00 Feb 4 08:00–12:00 Feb 5 09:00–14:00 Feb 6 10:00–13:00 Feb 7 08:00–12:00 Feb 12 08:00–11:00, 18:00–19:00 Feb 13 08:00–13:00 Feb 17 09:00–14:00 Feb 18 09:00–13:00 Feb 19 10:00–11:00 Feb 20 07:00–09:00, 19:00–21:00 Feb 21 07:00–12:00 Feb 22 18:00–22:00 Feb 25 07:00–13:00 Feb 26 08:00–13:00 Feb 27 09:00–12:00
March
Mar 4 08:00–13:00 Mar 8 18:00–22:00 Mar 9 13:00–16:00 Mar 11 20:00–22:00 Mar 12 10:00–13:00 Mar 13 18:00–22:00 Mar 14 08:00–13:00, 16:00–17:00 Mar 15 18:00–22:00 Mar 16 06:00–10:00 Mar 19 14:00–19:00 Mar 20 08:00–13:00 Mar 21 08:00–13:00 Mar 22 07:00–12:00 Mar 23 07:00–10:00 Mar 24 07:00–12:00, 20:00–22:00 Mar 25 07:00–12:00 Mar 27 08:00–13:00 Mar 28 09:00–11:00 Mar 29 18:00–21:00
April
Apr 1 07:00–12:00 Apr 2 07:00–11:00 Apr 9 07:00–11:00, 14:00–18:00 Apr 10 11:00–17:00 Apr 11 07:00–12:00 Apr 12 07:00–11:00, 17:00–20:00 Apr 13 07:00–10:00 Apr 15 07:00–11:00, 16:00–19:00 Apr 16 07:00–09:00 Apr 17 19:00–21:00 Apr 20 12:00–13:00 Apr 21 06:00–11:00 Apr 22 07:00–12:00, 18:00–20:00 Apr 23 09:00–10:00 Apr 24 06:00–11:00 Apr 25 02:00–05:00 Apr 26 15:00–19:00 Apr 27 10:00–11:00 Apr 29 07:00–12:00 Apr 30 08:00–11:00
May
May 1 07:00–10:00 May 2 17:00–22:00 May 3 06:00–11:00 May 4 06:00–11:00, 16:00–18:00 May 9 09:00–12:00 May 10 07:00–12:00 May 11 05:00–07:00 May 13 07:00–13:00 May 14 07:00–12:00 May 15 07:00–12:00 May 16 07:00–12:00 May 17 07:00–10:00 May 19 20:00–22:00 May 20 14:00–18:00 May 21 06:00–12:00 May 25 10:00–11:00 May 26 08:00–11:00 May 27 09:00–14:00 May 28 08:00–13:00 May 29 10:00–12:00
June
Jun 3 07:00–09:00 Jun 4 07:00–10:00 Jun 5 08:00–10:00 Jun 7 11:00–15:00 Jun 8 16:00–22:00 Jun 9 08:00–10:00 Jun 10 08:00–11:00 Jun 13 16:00–21:00 Jun 14 08:00–16:00 Jun 15 07:00–11:00 Jun 16 09:00–14:00 Jun 18 15:00–19:00 Jun 19 09:00–11:00, 20:00–24:00 Jun 24 07:00–10:00 Jun 25 07:00–11:00 Jun 26 08:00–13:00
July
Jul 1 17:00–22:00 Jul 2 10:00–14:00 Jul 3 09:00–14:00 Jul 4 08:00–13:00, 19:00–21:00 Jul 7 13:00–18:00 Jul 8 07:00–12:00 Jul 9 17:00–20:00 Jul 11 08:00–12:00 Jul 12 10:00–13:00 Jul 14 16:00–21:00 Jul 16 20:00–23:00 Jul 17 17:00–21:00 Jul 18 07:00–11:00 Jul 19 08:00–12:00 Jul 20 15:00–19:00 Jul 21 10:00–13:00 Jul 24 03:00–06:00 Jul 29 06:00–12:00 Jul 30 07:00–12:00 Jul 31 07:00–13:00
August
Aug 3 13:00–17:00 Aug 5 19:00–21:00 Aug 6 08:00–13:00 Aug 7 08:00–12:00 Aug 9 07:00–11:00 Aug 12 21:00–24:00 Aug 13 12:00–17:00 Aug 15 08:00–15:00, 19:00–21:00 Aug 16 08:00–12:00, 18:00–20:00 Aug 17 19:00–22:00 Aug 20 18:00–20:00 Aug 21 08:00–14:00 Aug 22 08:00–13:00 Aug 23 08:00–11:00, 17:00–20:00 Aug 28 11:00–15:00 Aug 29 08:00–14:00, 16:00–19:00 Aug 30 08:00–12:00, 18:00–20:00 Aug 31 09:00–14:00
September
Sep 1 11:00–15:00 Sep 2 18:00–23:00 Sep 3 22:00–24:00 Sep 4 00:00–01:00, 16:00–19:00 Sep 5 16:00–20:00 Sep 7 12:00–14:00 Sep 8 06:00–10:00, 18:00–20:00 Sep 9 07:00–11:00, 18:00–20:00 Sep 13 07:00–12:00, 19:00–22:00 Sep 14 14:00–18:00 Sep 15 17:00–21:00 Sep 16 08:00–13:00, 18:00–20:00 Sep 17 18:00–23:00 Sep 19 07:00–10:00 Sep 23 07:00–11:00 Sep 24 07:00–12:00, 19:00–22:00 Sep 25 08:00–11:00 Sep 26 19:00–23:00 Sep 27 20:00–22:00
October
Oct 2 07:00–09:00, 21:00–24:00 Oct 3 16:00–21:00 Oct 4 17:00–22:00 Oct 6 18:00–23:00 Oct 7 18:00–23:00 Oct 8 16:00–17:00 Oct 9 17:00–23:00 Oct 10 08:00–11:00 Oct 11 16:00–21:00 Oct 13 17:00–21:00 Oct 14 17:00–21:00 Oct 15 19:00–24:00 Oct 17 19:00–22:00 Oct 18 16:00–22:00 Oct 21 17:00–22:00 Oct 22 19:00–21:00 Oct 23 17:00–21:00 Oct 24 07:00–10:00 Oct 25 18:00–21:00 Oct 26 06:00–11:00 Oct 27 06:00–09:00, 16:00–20:00 Oct 28 06:00–11:00 Oct 29 07:00–11:00, 17:00–19:00 Oct 30 07:00–12:00 Oct 31 07:00–10:00
November
Nov 1 07:00–12:00, 17:00–18:00 Nov 2 07:00–13:00 Nov 4 17:00–21:00 Nov 5 06:00–11:00, 17:00–19:00 Nov 6 07:00–10:00, 17:00–20:00 Nov 7 08:00–11:00 Nov 8 10:00–15:00 Nov 10 08:00–10:00 Nov 11 08:00–13:00, 20:00–23:00 Nov 12 07:00–12:00 Nov 13 07:00–11:00 Nov 18 08:00–14:00 Nov 19 07:00–11:00, 19:00–21:00 Nov 20 06:00–11:00 Nov 22 07:00–12:00 Nov 23 07:00–12:00 Nov 25 07:00–11:00, 17:00–19:00 Nov 27 06:00–11:00 Nov 28 06:00–11:00, 18:00–20:00 Nov 29 07:00–11:00
December
Dec 1 05:00–10:00 Dec 2 06:00–11:00, 17:00–19:00 Dec 3 07:00–11:00, 17:00–20:00 Dec 4 07:00–11:00 Dec 5 07:00–11:00 Dec 6 07:00–11:00 Dec 9 07:00–11:00, 18:00–20:00 Dec 10 06:00–12:00 Dec 11 17:00–20:00 Dec 12 06:00–13:00, 17:00–18:00 Dec 13 07:00–11:00 Dec 16 07:00–12:00, 17:00–20:00 Dec 17 08:00–13:00 Dec 18 07:00–11:00, 17:00–20:00 Dec 19 07:00–09:00 Dec 20 15:00–21:00 Dec 22 07:00–11:00 Dec 23 07:00–12:00, 23:00–24:00 Dec 24 05:00–10:00 Dec 27 07:00–11:00, 18:00–21:00 Dec 28 07:00–09:00 Dec 29 08:00–10:00 Dec 30 07:00–12:00, 18:00–19:00