The 18-year-old initally joined the Stones on a one month’s loan in December, but that deal has now been extended by a further month.
Howes has made three appearances for Gordon Bartlett’s side, keeping one clean sheet to date.
The England under-18 international, who made his first-team debut for the Hammers eighteen months ago on a pre-season tour of New Zealand, was brought in to deputise for Jonathan North, who recently underwent knee surgery.