Most often in July, 27 days.
Highest follower count seen that year: 17,693.
January
Jan 2 02:00–06:00 Jan 5 01:00–08:00 Jan 6 06:00–09:00 Jan 7 04:00–06:00 Jan 9 04:00–07:00 Jan 10 02:00–06:00 Jan 11 01:00–07:00 Jan 12 03:00–07:00 Jan 13 07:00–09:00 Jan 14 03:00–08:00 Jan 15 04:00–06:00 Jan 16 14:00–16:00 Jan 17 02:00–07:00, 14:00–16:00 Jan 18 03:00–07:00 Jan 20 02:00–05:00 Jan 21 03:00–08:00 Jan 22 00:00–06:00 Jan 23 01:00–07:00 Jan 24 02:00–06:00 Jan 25 02:00–03:00, 12:00–14:00 Jan 27 01:00–04:00 Jan 28 02:00–06:00 Jan 29 03:00–07:00 Jan 30 02:00–05:00 Jan 31 03:00–04:00
February
Feb 1 13:00–16:00 Feb 2 03:00–05:00 Feb 3 02:00–05:00 Feb 4 02:00–07:00 Feb 5 03:00–07:00, 22:00–24:00 Feb 6 04:00–06:00 Feb 7 02:00–04:00 Feb 8 00:00–04:00 Feb 9 02:00–07:00 Feb 12 02:00–05:00, 15:00–17:00 Feb 13 03:00–06:00 Feb 14 01:00–06:00 Feb 15 01:00–06:00, 14:00–16:00 Feb 16 00:00–02:00 Feb 17 01:00–05:00, 22:00–24:00 Feb 18 00:00–04:00 Feb 19 03:00–07:00 Feb 20 01:00–05:00 Feb 21 01:00–05:00 Feb 23 03:00–07:00, 15:00–17:00 Feb 24 01:00–06:00, 22:00–24:00 Feb 25 00:00–04:00 Feb 26 01:00–04:00, 12:00–16:00 Feb 27 01:00–05:00 Feb 28 02:00–08:00
March
Mar 1 01:00–05:00 Mar 2 01:00–05:00, 22:00–24:00 Mar 3 00:00–05:00 Mar 4 01:00–06:00 Mar 5 02:00–04:00, 11:00–14:00 Mar 6 12:00–17:00 Mar 7 01:00–05:00 Mar 8 01:00–05:00, 15:00–17:00 Mar 9 01:00–05:00 Mar 10 00:00–05:00 Mar 12 03:00–07:00 Mar 13 03:00–05:00, 14:00–16:00, 23:00–24:00 Mar 14 00:00–04:00 Mar 16 02:00–05:00 Mar 17 10:00–16:00 Mar 18 11:00–15:00 Mar 19 11:00–15:00, 21:00–23:00 Mar 20 12:00–15:00 Mar 21 11:00–15:00 Mar 22 13:00–17:00 Mar 23 12:00–16:00 Mar 24 12:00–15:00 Mar 25 00:00–03:00 Mar 26 22:00–24:00 Mar 27 00:00–01:00
April
Apr 1 00:00–04:00 Apr 2 13:00–16:00 Apr 3 03:00–06:00, 12:00–15:00 Apr 4 02:00–06:00, 10:00–12:00 Apr 5 05:00–08:00 Apr 6 04:00–08:00 Apr 7 04:00–08:00, 13:00–15:00 Apr 8 05:00–08:00 Apr 9 04:00–08:00 Apr 12 03:00–08:00 Apr 13 03:00–06:00 Apr 14 06:00–09:00 Apr 16 03:00–07:00, 14:00–16:00 Apr 18 01:00–06:00 Apr 21 02:00–07:00 Apr 22 01:00–04:00 Apr 23 01:00–06:00 Apr 24 01:00–05:00 Apr 25 04:00–07:00 Apr 26 03:00–05:00 Apr 27 02:00–04:00 Apr 28 02:00–07:00 Apr 29 03:00–07:00 Apr 30 01:00–04:00
May
May 3 01:00–05:00 May 4 04:00–06:00, 12:00–14:00 May 5 01:00–03:00, 14:00–16:00 May 6 01:00–06:00, 14:00–16:00 May 7 01:00–04:00 May 8 03:00–06:00, 12:00–15:00 May 9 01:00–05:00 May 10 11:00–13:00 May 11 04:00–09:00, 12:00–13:00 May 15 01:00–03:00 May 17 01:00–04:00 May 18 13:00–16:00 May 19 00:00–04:00 May 20 02:00–07:00 May 21 01:00–06:00 May 22 01:00–04:00, 21:00–24:00 May 23 00:00–04:00 May 24 01:00–06:00 May 25 01:00–05:00 May 26 00:00–06:00 May 27 01:00–05:00 May 28 01:00–05:00 May 29 01:00–06:00 May 30 00:00–06:00 May 31 00:00–03:00
June
Jun 1 00:00–05:00 Jun 2 00:00–06:00 Jun 3 00:00–04:00 Jun 5 01:00–05:00 Jun 6 01:00–06:00 Jun 7 01:00–05:00 Jun 8 01:00–05:00 Jun 9 01:00–05:00 Jun 10 09:00–14:00 Jun 11 05:00–09:00 Jun 13 12:00–16:00 Jun 14 02:00–06:00 Jun 15 04:00–07:00 Jun 16 01:00–06:00 Jun 18 04:00–09:00 Jun 19 03:00–08:00 Jun 20 01:00–06:00 Jun 21 03:00–09:00 Jun 22 03:00–08:00 Jun 24 03:00–09:00 Jun 25 04:00–07:00 Jun 26 04:00–09:00 Jun 27 03:00–07:00 Jun 28 02:00–07:00, 11:00–14:00 Jun 29 02:00–08:00
July
Jul 2 08:00–13:00 Jul 3 02:00–09:00 Jul 4 04:00–09:00 Jul 5 04:00–08:00, 12:00–16:00 Jul 6 04:00–07:00 Jul 7 04:00–08:00, 21:00–24:00 Jul 8 00:00–03:00 Jul 10 05:00–10:00 Jul 11 05:00–08:00, 14:00–16:00 Jul 12 07:00–13:00 Jul 13 11:00–12:00 Jul 14 11:00–15:00 Jul 15 07:00–12:00 Jul 16 08:00–12:00 Jul 17 11:00–14:00 Jul 18 12:00–16:00 Jul 19 06:00–10:00, 12:00–14:00 Jul 21 07:00–11:00 Jul 22 08:00–09:00, 11:00–14:00 Jul 23 04:00–07:00 Jul 25 05:00–07:00, 10:00–11:00 Jul 26 06:00–10:00 Jul 27 04:00–08:00, 13:00–15:00 Jul 28 06:00–10:00 Jul 29 06:00–13:00, 16:00–18:00 Jul 30 03:00–06:00, 11:00–15:00, 23:00–24:00 Jul 31 00:00–02:00, 12:00–14:00
August
Aug 1 10:00–16:00 Aug 2 10:00–15:00 Aug 3 09:00–12:00, 14:00–17:00 Aug 4 07:00–13:00 Aug 6 10:00–12:00 Aug 7 09:00–13:00 Aug 8 08:00–13:00 Aug 10 07:00–12:00 Aug 11 08:00–12:00 Aug 12 08:00–13:00 Aug 13 00:00–03:00 Aug 14 11:00–14:00 Aug 15 08:00–15:00 Aug 16 03:00–06:00, 12:00–14:00 Aug 17 12:00–13:00 Aug 18 05:00–08:00
September
Sep 25 05:00–06:00 Sep 26 04:00–08:00 Sep 27 04:00–09:00, 13:00–15:00 Sep 28 14:00–18:00 Sep 29 05:00–11:00 Sep 30 03:00–06:00
October
Oct 1 03:00–09:00, 12:00–15:00 Oct 2 03:00–09:00 Oct 3 03:00–09:00 Oct 4 05:00–07:00, 12:00–17:00 Oct 5 03:00–07:00 Oct 6 03:00–07:00 Oct 7 03:00–09:00 Oct 8 03:00–08:00 Oct 9 03:00–09:00 Oct 11 03:00–05:00, 11:00–14:00 Oct 12 03:00–09:00, 12:00–15:00 Oct 13 03:00–09:00 Oct 14 05:00–08:00 Oct 15 03:00–09:00, 13:00–15:00 Oct 16 03:00–07:00, 13:00–14:00 Oct 17 03:00–09:00 Oct 19 03:00–08:00 Oct 20 04:00–12:00 Oct 21 01:00–04:00, 07:00–11:00 Oct 22 05:00–08:00 Oct 23 05:00–11:00, 13:00–17:00 Oct 24 04:00–09:00 Oct 28 03:00–08:00 Oct 29 04:00–07:00 Oct 30 04:00–08:00 Oct 31 04:00–06:00, 09:00–10:00
November
Nov 1 08:00–14:00 Nov 3 08:00–13:00 Nov 5 07:00–13:00 Nov 6 03:00–06:00, 09:00–14:00 Nov 7 06:00–12:00 Nov 8 04:00–12:00 Nov 9 09:00–14:00 Nov 10 05:00–09:00 Nov 13 05:00–13:00 Nov 14 07:00–13:00 Nov 15 06:00–10:00 Nov 16 06:00–12:00 Nov 17 05:00–10:00, 14:00–16:00 Nov 19 04:00–12:00 Nov 20 05:00–13:00 Nov 21 05:00–10:00 Nov 22 05:00–11:00 Nov 23 06:00–13:00 Nov 24 03:00–08:00 Nov 27 04:00–07:00 Nov 28 04:00–07:00, 10:00–13:00
December
Dec 1 04:00–11:00 Dec 2 05:00–11:00 Dec 4 04:00–12:00 Dec 5 05:00–12:00 Dec 6 06:00–12:00 Dec 7 06:00–10:00 Dec 8 04:00–09:00, 23:00–24:00 Dec 9 00:00–06:00 Dec 11 07:00–11:00 Dec 12 05:00–11:00 Dec 13 06:00–13:00 Dec 14 06:00–09:00, 11:00–13:00 Dec 15 05:00–12:00 Dec 18 03:00–11:00 Dec 19 03:00–10:00 Dec 20 04:00–11:00 Dec 21 05:00–09:00 Dec 22 04:00–07:00, 12:00–16:00 Dec 23 06:00–09:00 Dec 24 03:00–07:00 Dec 25 05:00–12:00 Dec 26 12:00–15:00 Dec 27 01:00–04:00, 08:00–11:00 Dec 28 08:00–12:00 Dec 29 10:00–14:00 Dec 31 05:00–10:00