Most often in July, 30 days.
Highest follower count seen that year: 7,128.
June
Jun 9 00:00–02:00, 07:00–15:00, 17:00–24:00 Jun 10 00:00–01:00, 09:00–11:00, 13:00–24:00 Jun 11 00:00–02:00, 06:00–07:00, 19:00–24:00 Jun 12 00:00–09:00, 12:00–19:00, 22:00–24:00 Jun 13 00:00–06:00, 11:00–12:00, 16:00–23:00 Jun 14 00:00–09:00, 11:00–13:00, 18:00–24:00 Jun 15 02:00–06:00, 09:00–15:00, 17:00–23:00 Jun 16 04:00–09:00, 14:00–24:00 Jun 17 00:00–01:00, 04:00–07:00, 10:00–11:00, 17:00–22:00 Jun 18 01:00–07:00, 12:00–24:00 Jun 19 00:00–08:00, 12:00–14:00, 16:00–23:00 Jun 20 01:00–04:00, 08:00–15:00, 17:00–23:00 Jun 21 01:00–07:00, 12:00–14:00, 16:00–24:00 Jun 22 00:00–09:00, 11:00–14:00, 16:00–23:00 Jun 23 00:00–07:00, 13:00–17:00, 20:00–24:00 Jun 24 01:00–07:00, 16:00–22:00 Jun 25 01:00–11:00, 19:00–24:00 Jun 26 01:00–09:00, 14:00–16:00, 19:00–24:00 Jun 27 03:00–07:00, 16:00–24:00 Jun 28 00:00–06:00, 10:00–13:00, 19:00–22:00 Jun 29 01:00–08:00, 15:00–17:00, 20:00–24:00 Jun 30 00:00–08:00, 19:00–23:00
July
Jul 1 02:00–08:00, 13:00–16:00, 18:00–19:00 Jul 2 01:00–07:00 Jul 3 18:00–20:00 Jul 4 01:00–10:00, 17:00–18:00, 23:00–24:00 Jul 5 00:00–10:00, 16:00–19:00 Jul 6 00:00–13:00, 18:00–19:00, 21:00–24:00 Jul 7 00:00–01:00, 04:00–08:00, 13:00–14:00, 19:00–24:00 Jul 8 01:00–07:00, 20:00–22:00 Jul 9 02:00–08:00, 22:00–24:00 Jul 10 00:00–07:00, 22:00–23:00 Jul 11 01:00–08:00, 14:00–17:00, 19:00–21:00 Jul 12 01:00–07:00, 13:00–17:00, 22:00–24:00 Jul 13 00:00–09:00, 14:00–20:00 Jul 14 02:00–07:00, 15:00–17:00, 19:00–20:00, 22:00–23:00 Jul 15 01:00–02:00, 05:00–10:00, 15:00–23:00 Jul 16 02:00–10:00, 19:00–22:00 Jul 17 02:00–04:00, 06:00–09:00, 14:00–24:00 Jul 18 05:00–07:00, 14:00–20:00, 22:00–23:00 Jul 19 01:00–03:00, 06:00–11:00, 14:00–17:00, 19:00–24:00 Jul 20 00:00–01:00, 05:00–07:00, 12:00–24:00 Jul 21 03:00–08:00, 16:00–22:00 Jul 22 02:00–08:00, 17:00–23:00 Jul 23 01:00–09:00, 13:00–17:00 Jul 24 12:00–24:00 Jul 25 00:00–06:00, 14:00–15:00, 18:00–23:00 Jul 26 04:00–08:00, 13:00–22:00 Jul 27 15:00–24:00 Jul 28 00:00–03:00, 18:00–21:00 Jul 29 00:00–06:00, 18:00–24:00 Jul 30 01:00–06:00, 20:00–21:00
August
Aug 2 21:00–24:00 Aug 3 00:00–02:00, 10:00–13:00, 17:00–24:00 Aug 4 00:00–07:00, 18:00–24:00 Aug 5 08:00–09:00, 18:00–24:00 Aug 6 00:00–01:00, 06:00–09:00, 18:00–24:00 Aug 7 00:00–06:00, 15:00–16:00, 18:00–24:00 Aug 8 00:00–06:00, 20:00–24:00 Aug 9 00:00–06:00, 20:00–24:00 Aug 10 00:00–07:00, 17:00–24:00 Aug 11 00:00–05:00, 21:00–23:00 Aug 12 00:00–01:00, 04:00–06:00, 18:00–24:00 Aug 13 00:00–07:00, 18:00–24:00 Aug 14 02:00–05:00, 13:00–16:00 Aug 15 18:00–24:00 Aug 16 00:00–08:00, 18:00–24:00 Aug 17 00:00–05:00, 16:00–24:00 Aug 18 00:00–04:00, 20:00–24:00 Aug 19 00:00–05:00, 19:00–24:00 Aug 20 00:00–03:00, 18:00–24:00 Aug 21 00:00–03:00, 23:00–24:00 Aug 22 01:00–03:00, 19:00–24:00 Aug 23 00:00–05:00, 19:00–24:00 Aug 24 00:00–01:00, 03:00–06:00, 20:00–24:00 Aug 25 00:00–05:00, 19:00–24:00 Aug 26 00:00–02:00, 19:00–24:00 Aug 27 01:00–05:00 Aug 28 20:00–22:00 Aug 31 15:00–24:00
September
Sep 1 00:00–04:00, 19:00–24:00 Sep 2 00:00–02:00 Sep 3 05:00–08:00, 19:00–24:00 Sep 4 00:00–01:00, 19:00–24:00 Sep 5 00:00–02:00, 18:00–24:00 Sep 6 00:00–03:00, 20:00–24:00 Sep 7 00:00–05:00, 21:00–24:00 Sep 8 00:00–02:00, 21:00–24:00 Sep 9 22:00–24:00 Sep 10 00:00–04:00, 20:00–24:00 Sep 11 00:00–01:00, 19:00–24:00 Sep 12 00:00–04:00, 20:00–24:00 Sep 13 00:00–03:00, 20:00–24:00 Sep 14 00:00–03:00, 19:00–24:00 Sep 15 00:00–02:00, 23:00–24:00 Sep 16 20:00–24:00 Sep 17 00:00–02:00, 20:00–24:00 Sep 18 00:00–02:00, 20:00–24:00 Sep 19 00:00–02:00 Sep 20 00:00–02:00 Sep 21 19:00–24:00 Sep 22 00:00–02:00 Sep 23 21:00–24:00 Sep 24 00:00–02:00, 22:00–24:00 Sep 25 00:00–02:00 Sep 30 20:00–24:00
October
Oct 1 00:00–01:00, 20:00–24:00 Oct 2 00:00–01:00, 21:00–23:00 Oct 3 01:00–03:00 Oct 4 00:00–02:00, 21:00–24:00 Oct 6 00:00–06:00 Oct 7 21:00–24:00 Oct 8 00:00–01:00, 21:00–24:00 Oct 9 00:00–01:00, 21:00–24:00 Oct 10 00:00–01:00, 21:00–24:00 Oct 11 01:00–03:00 Oct 12 20:00–24:00 Oct 13 00:00–02:00, 21:00–23:00 Oct 14 20:00–24:00 Oct 15 01:00–03:00, 20:00–23:00 Oct 16 00:00–03:00 Oct 17 21:00–24:00 Oct 18 21:00–24:00 Oct 19 00:00–02:00 Oct 20 03:00–05:00, 20:00–24:00 Oct 21 00:00–03:00, 20:00–23:00 Oct 22 03:00–04:00, 20:00–24:00 Oct 23 00:00–01:00, 21:00–24:00
November
Nov 4 19:00–22:00 Nov 5 20:00–24:00 Nov 6 00:00–02:00, 23:00–24:00 Nov 7 00:00–02:00, 21:00–24:00 Nov 8 00:00–01:00, 22:00–24:00 Nov 9 20:00–24:00 Nov 10 00:00–01:00 Nov 11 21:00–24:00 Nov 12 00:00–02:00, 21:00–24:00 Nov 13 01:00–02:00, 20:00–24:00 Nov 14 00:00–01:00, 20:00–23:00 Nov 15 01:00–03:00, 22:00–24:00 Nov 16 00:00–02:00, 20:00–23:00 Nov 17 00:00–04:00, 21:00–24:00 Nov 18 00:00–02:00, 22:00–24:00 Nov 20 20:00–24:00 Nov 21 21:00–24:00 Nov 22 01:00–03:00 Nov 26 20:00–24:00 Nov 27 00:00–02:00, 20:00–22:00 Nov 28 00:00–01:00, 20:00–24:00 Nov 29 00:00–02:00, 21:00–24:00 Nov 30 00:00–03:00, 20:00–24:00
December
Dec 1 00:00–03:00, 21:00–24:00 Dec 2 00:00–02:00 Dec 9 02:00–04:00, 20:00–24:00 Dec 10 20:00–21:00 Dec 11 01:00–03:00, 21:00–23:00 Dec 12 00:00–02:00, 20:00–23:00 Dec 13 00:00–01:00 Dec 14 00:00–02:00, 20:00–24:00 Dec 15 00:00–01:00, 20:00–24:00 Dec 16 00:00–03:00 Dec 17 14:00–15:00, 20:00–23:00 Dec 18 02:00–04:00, 20:00–22:00 Dec 23 20:00–23:00 Dec 24 20:00–24:00 Dec 27 20:00–21:00 Dec 28 20:00–24:00 Dec 30 21:00–23:00