Most often in July, 31 days.
Highest follower count seen that year: 39,920.
January
Jan 1 06:00–11:00 Jan 2 05:00–12:00 Jan 3 06:00–10:00 Jan 4 05:00–10:00 Jan 5 05:00–09:00 Jan 6 06:00–10:00 Jan 7 06:00–09:00 Jan 8 05:00–10:00 Jan 10 05:00–08:00 Jan 11 04:00–09:00 Jan 12 06:00–10:00 Jan 13 05:00–09:00 Jan 14 04:00–08:00 Jan 15 06:00–09:00 Jan 18 03:00–09:00 Jan 19 05:00–08:00 Jan 20 05:00–10:00 Jan 21 04:00–08:00 Jan 22 05:00–10:00 Jan 23 03:00–10:00 Jan 24 05:00–09:00 Jan 25 05:00–10:00 Jan 26 06:00–10:00 Jan 27 05:00–10:00 Jan 28 05:00–09:00 Jan 29 05:00–09:00 Jan 30 03:00–07:00 Jan 31 04:00–08:00
February
Feb 1 05:00–10:00 Feb 2 06:00–09:00 Feb 3 07:00–09:00 Feb 4 05:00–08:00 Feb 5 06:00–10:00 Feb 7 06:00–09:00 Feb 8 05:00–10:00 Feb 9 06:00–08:00 Feb 10 05:00–09:00 Feb 11 06:00–09:00 Feb 12 05:00–08:00 Feb 13 04:00–09:00
March
Mar 14 05:00–12:00 Mar 16 08:00–11:00 Mar 17 04:00–10:00 Mar 18 06:00–12:00 Mar 19 04:00–06:00 Mar 20 07:00–10:00 Mar 21 04:00–09:00 Mar 22 07:00–11:00 Mar 23 09:00–11:00 Mar 24 06:00–10:00 Mar 25 05:00–10:00 Mar 26 06:00–11:00 Mar 27 06:00–11:00 Mar 28 05:00–10:00 Mar 29 06:00–10:00 Mar 31 05:00–10:00
April
Apr 1 05:00–10:00 Apr 2 06:00–08:00 Apr 3 04:00–09:00 Apr 4 05:00–09:00 Apr 5 06:00–11:00 Apr 6 06:00–07:00, 09:00–11:00 Apr 7 06:00–07:00, 09:00–11:00 Apr 8 05:00–10:00 Apr 9 05:00–08:00 Apr 10 04:00–11:00 Apr 11 05:00–09:00 Apr 12 06:00–10:00 Apr 13 05:00–09:00 Apr 14 04:00–11:00 Apr 15 04:00–11:00 Apr 16 04:00–10:00 Apr 17 04:00–11:00 Apr 19 05:00–06:00, 08:00–10:00 Apr 21 04:00–08:00 Apr 22 04:00–10:00 Apr 23 04:00–11:00 Apr 24 04:00–10:00 Apr 25 05:00–10:00 Apr 26 06:00–11:00 Apr 27 06:00–11:00, 15:00–16:00 Apr 28 06:00–11:00 Apr 29 05:00–10:00 Apr 30 06:00–09:00
May
May 1 03:00–09:00 May 2 05:00–06:00, 09:00–10:00 May 3 04:00–11:00 May 4 05:00–10:00 May 5 06:00–12:00 May 6 04:00–08:00 May 7 04:00–10:00 May 8 04:00–07:00 May 9 05:00–10:00 May 10 05:00–09:00 May 11 05:00–09:00 May 12 08:00–10:00 May 13 06:00–11:00 May 14 05:00–11:00 May 15 04:00–05:00, 08:00–11:00 May 16 04:00–11:00 May 17 03:00–10:00 May 18 07:00–11:00 May 19 06:00–09:00 May 20 04:00–11:00 May 21 06:00–07:00, 09:00–11:00 May 22 04:00–11:00 May 23 03:00–11:00 May 24 03:00–11:00 May 26 03:00–05:00, 09:00–11:00 May 27 04:00–11:00 May 28 03:00–07:00, 09:00–10:00 May 29 05:00–11:00 May 30 04:00–11:00 May 31 05:00–10:00
June
Jun 1 06:00–09:00 Jun 2 05:00–10:00 Jun 3 04:00–11:00 Jun 4 04:00–12:00 Jun 5 05:00–12:00 Jun 6 05:00–11:00 Jun 7 06:00–12:00 Jun 8 06:00–08:00 Jun 9 06:00–12:00 Jun 10 05:00–11:00 Jun 12 08:00–12:00 Jun 13 05:00–10:00 Jun 14 06:00–09:00 Jun 15 06:00–07:00 Jun 16 05:00–08:00 Jun 17 05:00–10:00 Jun 20 05:00–11:00 Jun 21 07:00–09:00 Jun 22 05:00–08:00 Jun 23 05:00–06:00, 08:00–12:00 Jun 24 06:00–11:00 Jun 25 04:00–12:00 Jun 26 05:00–09:00 Jun 27 05:00–09:00 Jun 29 07:00–12:00 Jun 30 05:00–11:00
July
Jul 1 07:00–11:00 Jul 2 07:00–12:00 Jul 3 07:00–12:00 Jul 4 06:00–12:00 Jul 5 05:00–08:00 Jul 6 06:00–07:00 Jul 7 04:00–12:00 Jul 8 05:00–12:00 Jul 9 05:00–13:00 Jul 10 06:00–12:00 Jul 11 05:00–11:00 Jul 12 08:00–12:00 Jul 13 06:00–07:00 Jul 14 10:00–13:00 Jul 15 04:00–12:00 Jul 16 06:00–10:00 Jul 17 07:00–13:00 Jul 18 05:00–10:00 Jul 19 06:00–08:00 Jul 20 05:00–07:00 Jul 21 05:00–12:00 Jul 22 05:00–11:00 Jul 23 05:00–11:00 Jul 24 05:00–09:00, 11:00–12:00 Jul 25 05:00–11:00 Jul 26 06:00–10:00 Jul 27 05:00–06:00 Jul 28 07:00–12:00 Jul 29 08:00–12:00 Jul 30 05:00–11:00 Jul 31 05:00–12:00
August
Aug 1 05:00–11:00 Aug 2 06:00–11:00 Aug 3 08:00–09:00 Aug 4 05:00–11:00 Aug 5 08:00–10:00 Aug 6 07:00–12:00 Aug 7 07:00–11:00 Aug 8 06:00–08:00 Aug 9 06:00–10:00 Aug 10 05:00–08:00 Aug 11 05:00–07:00 Aug 12 05:00–10:00 Aug 13 05:00–12:00 Aug 14 04:00–07:00, 10:00–12:00 Aug 15 07:00–11:00 Aug 16 06:00–09:00 Aug 17 05:00–08:00 Aug 18 05:00–11:00 Aug 19 05:00–10:00 Aug 20 05:00–12:00 Aug 21 05:00–12:00 Aug 22 05:00–12:00 Aug 23 07:00–11:00 Aug 24 06:00–08:00 Aug 26 06:00–08:00, 10:00–12:00 Aug 27 06:00–12:00 Aug 28 05:00–12:00 Aug 29 05:00–10:00 Aug 31 06:00–08:00
September
Sep 1 07:00–12:00 Sep 2 07:00–13:00 Sep 3 05:00–11:00 Sep 4 06:00–12:00 Sep 5 06:00–11:00 Sep 6 07:00–11:00 Sep 7 07:00–10:00 Sep 8 05:00–08:00, 11:00–12:00 Sep 9 06:00–12:00 Sep 10 06:00–13:00 Sep 11 06:00–12:00 Sep 12 06:00–12:00 Sep 13 07:00–11:00 Sep 14 06:00–08:00 Sep 15 06:00–11:00 Sep 16 05:00–11:00 Sep 17 06:00–12:00 Sep 18 05:00–10:00 Sep 19 05:00–11:00 Sep 20 05:00–11:00 Sep 21 07:00–08:00 Sep 22 06:00–12:00 Sep 23 06:00–11:00 Sep 24 05:00–12:00 Sep 25 05:00–12:00 Sep 26 06:00–09:00 Sep 27 07:00–12:00 Sep 28 07:00–11:00 Sep 29 05:00–12:00 Sep 30 05:00–12:00
October
Oct 1 06:00–13:00 Oct 2 06:00–12:00 Oct 3 06:00–12:00 Oct 4 08:00–09:00 Oct 6 04:00–09:00 Oct 7 05:00–12:00 Oct 8 05:00–10:00 Oct 9 06:00–13:00 Oct 10 07:00–10:00 Oct 11 06:00–09:00
November
Nov 12 06:00–11:00 Nov 13 04:00–09:00 Nov 15 08:00–12:00 Nov 16 07:00–12:00 Nov 17 06:00–10:00 Nov 18 06:00–09:00 Nov 19 06:00–10:00 Nov 20 06:00–10:00 Nov 21 06:00–10:00 Nov 22 05:00–10:00 Nov 23 05:00–11:00 Nov 24 06:00–10:00 Nov 25 06:00–10:00 Nov 26 05:00–10:00 Nov 27 05:00–08:00 Nov 29 07:00–11:00 Nov 30 07:00–11:00
December
Dec 1 05:00–10:00 Dec 2 06:00–08:00 Dec 3 06:00–11:00 Dec 5 06:00–09:00 Dec 6 07:00–11:00 Dec 8 06:00–11:00 Dec 9 06:00–11:00 Dec 10 05:00–10:00 Dec 11 06:00–11:00 Dec 12 07:00–10:00 Dec 13 06:00–11:00 Dec 14 07:00–12:00 Dec 16 06:00–07:00, 09:00–10:00 Dec 17 07:00–11:00 Dec 18 07:00–11:00 Dec 20 04:00–10:00 Dec 21 05:00–11:00 Dec 22 07:00–09:00 Dec 24 03:00–07:00 Dec 27 09:00–11:00 Dec 28 07:00–10:00 Dec 30 08:00–12:00 Dec 31 03:00–05:00, 07:00–08:00