diff --git a/docker/chatmail_relay.dockerfile b/docker/chatmail_relay.dockerfile
index f54d76db..b06c7ecb 100644
--- a/docker/chatmail_relay.dockerfile
+++ b/docker/chatmail_relay.dockerfile
@@ -74,6 +74,7 @@ RUN echo "$GIT_HASH" > /etc/chatmail-image-version && \
 # --- End build-time install ---
 
 ENV CHATMAIL_INI=/etc/chatmail/chatmail.ini
+ENV TZ=:/etc/localtime
 ENV PATH="/opt/cmdeploy/bin:${PATH}"
 RUN ln -s /etc/chatmail/chatmail.ini /opt/chatmail/chatmail.ini