Most often in November, 30 days.
Highest follower count seen that year: 2,660.
July
Jul 28 01:00–05:00, 09:00–14:00, 18:00–20:00 UTC Jul 29 04:00–06:00, 10:00–20:00 UTC Jul 30 07:00–20:00, 22:00–24:00 UTC Jul 31 09:00–13:00, 15:00–23:00 UTC
August
Aug 1 03:00–05:00, 10:00–23:00 UTC Aug 2 08:00–21:00 UTC Aug 3 03:00–06:00, 12:00–16:00, 19:00–20:00 UTC Aug 4 10:00–15:00, 17:00–19:00 UTC Aug 5 10:00–12:00, 14:00–19:00 UTC Aug 6 04:00–05:00, 09:00–11:00, 13:00–14:00, 16:00–20:00 UTC Aug 7 09:00–11:00, 13:00–14:00, 18:00–19:00 UTC Aug 11 21:00–22:00 UTC Aug 12 02:00–05:00, 07:00–08:00, 10:00–19:00 UTC Aug 13 05:00–06:00, 09:00–21:00 UTC Aug 14 03:00–05:00, 10:00–13:00, 15:00–19:00 UTC Aug 15 02:00–08:00, 10:00–17:00 UTC Aug 16 01:00–05:00, 08:00–20:00 UTC Aug 17 03:00–06:00, 10:00–14:00, 17:00–19:00 UTC Aug 18 06:00–09:00, 11:00–21:00 UTC Aug 19 07:00–20:00 UTC Aug 20 06:00–13:00, 16:00–19:00 UTC Aug 21 02:00–05:00, 07:00–12:00, 14:00–15:00, 17:00–19:00 UTC Aug 22 06:00–19:00 UTC Aug 23 02:00–07:00, 11:00–18:00 UTC Aug 24 07:00–14:00, 17:00–21:00 UTC Aug 25 14:00–20:00 UTC Aug 26 03:00–05:00, 10:00–11:00, 14:00–20:00 UTC Aug 27 02:00–05:00, 10:00–14:00, 16:00–17:00, 19:00–22:00 UTC Aug 28 06:00–15:00, 17:00–19:00 UTC Aug 29 02:00–04:00, 08:00–10:00 UTC Aug 30 02:00–17:00, 19:00–20:00 UTC Aug 31 02:00–05:00, 09:00–14:00, 19:00–20:00 UTC
September
Sep 1 03:00–04:00, 08:00–12:00, 15:00–19:00 UTC Sep 2 03:00–05:00, 09:00–20:00 UTC Sep 3 02:00–06:00, 10:00–12:00, 14:00–21:00 UTC Sep 4 02:00–05:00, 09:00–11:00, 16:00–21:00 UTC Sep 5 08:00–14:00, 17:00–18:00, 21:00–23:00 UTC Sep 6 02:00–04:00, 10:00–15:00, 17:00–24:00 UTC Sep 7 10:00–16:00 UTC Sep 8 01:00–03:00 UTC Sep 9 18:00–19:00 UTC Sep 10 02:00–06:00, 08:00–10:00, 16:00–18:00 UTC Sep 11 02:00–04:00, 08:00–14:00, 16:00–22:00 UTC Sep 12 06:00–10:00, 12:00–19:00 UTC Sep 13 02:00–04:00, 10:00–15:00, 17:00–21:00 UTC Sep 14 02:00–06:00, 12:00–16:00, 18:00–19:00, 23:00–24:00 UTC Sep 15 03:00–04:00, 09:00–10:00, 12:00–16:00, 18:00–19:00 UTC Sep 16 02:00–05:00, 10:00–16:00, 18:00–24:00 UTC Sep 17 00:00–03:00, 11:00–21:00 UTC Sep 18 10:00–20:00 UTC Sep 19 01:00–04:00, 11:00–15:00, 18:00–22:00 UTC Sep 20 07:00–14:00, 16:00–23:00 UTC Sep 21 00:00–01:00, 04:00–08:00, 13:00–17:00 UTC Sep 22 01:00–04:00 UTC Sep 23 17:00–20:00 UTC Sep 24 01:00–04:00, 09:00–13:00, 15:00–17:00 UTC Sep 25 09:00–21:00 UTC Sep 26 14:00–23:00 UTC Sep 27 02:00–05:00, 11:00–13:00, 15:00–18:00 UTC Sep 28 03:00–10:00, 14:00–20:00 UTC Sep 29 08:00–15:00, 17:00–18:00 UTC Sep 30 06:00–12:00, 14:00–15:00, 18:00–21:00 UTC
October
Oct 1 07:00–13:00, 16:00–22:00 UTC Oct 2 04:00–06:00, 08:00–12:00, 17:00–20:00 UTC Oct 3 04:00–07:00, 11:00–20:00 UTC Oct 4 07:00–12:00, 15:00–16:00, 18:00–21:00 UTC Oct 5 05:00–08:00, 13:00–23:00 UTC Oct 6 04:00–06:00, 11:00–15:00 UTC Oct 7 03:00–05:00, 08:00–14:00, 18:00–22:00 UTC Oct 8 06:00–10:00, 14:00–23:00 UTC Oct 9 09:00–22:00 UTC Oct 10 01:00–03:00 UTC Oct 13 17:00–20:00 UTC Oct 14 02:00–06:00, 10:00–14:00, 18:00–20:00 UTC Oct 15 03:00–06:00, 10:00–14:00, 17:00–21:00 UTC Oct 16 03:00–07:00, 11:00–16:00, 18:00–19:00 UTC Oct 17 04:00–05:00, 09:00–12:00, 17:00–22:00 UTC Oct 18 03:00–06:00, 10:00–13:00, 16:00–22:00 UTC Oct 19 01:00–03:00, 11:00–13:00, 15:00–20:00 UTC Oct 20 06:00–08:00, 11:00–19:00, 21:00–24:00 UTC Oct 21 09:00–19:00 UTC Oct 22 06:00–21:00 UTC Oct 23 06:00–08:00, 11:00–17:00 UTC Oct 24 01:00–02:00, 06:00–09:00, 11:00–13:00, 16:00–21:00 UTC Oct 25 04:00–06:00, 11:00–15:00, 18:00–19:00 UTC Oct 26 05:00–06:00, 08:00–10:00, 15:00–19:00 UTC Oct 27 08:00–15:00, 17:00–20:00 UTC Oct 28 10:00–19:00 UTC Oct 29 04:00–06:00, 09:00–14:00, 18:00–19:00 UTC Oct 30 02:00–04:00, 09:00–12:00, 15:00–20:00 UTC Oct 31 03:00–05:00, 10:00–20:00 UTC
November
Nov 1 05:00–10:00, 12:00–19:00 UTC Nov 2 05:00–12:00, 17:00–20:00 UTC Nov 3 04:00–06:00, 08:00–12:00, 14:00–16:00, 18:00–19:00 UTC Nov 4 04:00–10:00, 13:00–15:00, 17:00–18:00 UTC Nov 5 02:00–06:00, 09:00–11:00, 14:00–15:00, 17:00–20:00 UTC Nov 6 05:00–09:00, 12:00–21:00 UTC Nov 7 05:00–06:00, 09:00–12:00, 14:00–22:00 UTC Nov 8 02:00–04:00, 06:00–11:00, 16:00–20:00 UTC Nov 9 04:00–07:00, 19:00–20:00 UTC Nov 10 05:00–20:00 UTC Nov 11 05:00–10:00, 15:00–20:00 UTC Nov 12 02:00–05:00, 08:00–11:00, 16:00–17:00 UTC Nov 13 06:00–14:00, 16:00–17:00 UTC Nov 14 07:00–12:00, 14:00–16:00, 18:00–20:00 UTC Nov 15 02:00–04:00, 08:00–12:00, 14:00–20:00 UTC Nov 16 01:00–04:00, 08:00–12:00, 15:00–19:00 UTC Nov 17 02:00–20:00 UTC Nov 18 02:00–05:00, 08:00–12:00, 14:00–15:00, 17:00–19:00 UTC Nov 19 02:00–08:00, 12:00–19:00 UTC Nov 20 03:00–06:00, 11:00–12:00 UTC Nov 21 08:00–20:00 UTC Nov 22 03:00–05:00, 07:00–17:00 UTC Nov 23 02:00–05:00, 07:00–08:00, 15:00–19:00 UTC Nov 24 00:00–04:00, 08:00–12:00, 15:00–19:00 UTC Nov 25 02:00–04:00, 08:00–10:00, 14:00–15:00 UTC Nov 26 02:00–03:00, 07:00–09:00, 12:00–20:00 UTC Nov 27 03:00–06:00, 09:00–10:00, 16:00–20:00 UTC Nov 28 03:00–05:00, 07:00–20:00 UTC Nov 29 06:00–08:00, 10:00–22:00 UTC Nov 30 03:00–06:00, 09:00–13:00, 15:00–18:00 UTC
December
Dec 1 14:00–21:00 UTC Dec 2 02:00–05:00, 08:00–14:00, 16:00–21:00 UTC Dec 3 09:00–16:00, 18:00–19:00 UTC Dec 4 03:00–05:00, 09:00–15:00, 18:00–22:00 UTC Dec 5 04:00–07:00, 11:00–20:00 UTC Dec 6 03:00–07:00, 10:00–16:00, 18:00–19:00 UTC Dec 7 04:00–06:00, 13:00–22:00 UTC Dec 8 02:00–04:00, 09:00–18:00, 20:00–22:00 UTC Dec 9 02:00–06:00, 12:00–20:00 UTC Dec 10 04:00–10:00, 14:00–22:00 UTC Dec 11 00:00–04:00, 10:00–15:00, 20:00–24:00 UTC Dec 12 00:00–03:00, 10:00–24:00 UTC Dec 13 00:00–02:00, 10:00–24:00 UTC Dec 14 00:00–03:00, 11:00–14:00, 16:00–24:00 UTC Dec 15 00:00–03:00, 12:00–14:00, 18:00–24:00 UTC Dec 16 00:00–01:00, 10:00–15:00, 17:00–24:00 UTC Dec 17 00:00–03:00, 07:00–11:00, 15:00–24:00 UTC Dec 18 00:00–03:00, 09:00–10:00, 15:00–19:00 UTC Dec 19 08:00–09:00, 12:00–17:00, 19:00–24:00 UTC Dec 20 07:00–09:00, 15:00–24:00 UTC Dec 21 00:00–03:00, 11:00–17:00, 22:00–24:00 UTC