Sometimes I'm unable to create a database in UTF8 encoding because the template database is in the ASCII encoding. To fix it we need to recreate template database in UTF8.
Start psql console:
Run the following commands:
UPDATE pg_database SET datistemplate = FALSE WHERE datname = 'template1';
CREATE DATABASE template1 WITH TEMPLATE = template0 ENCODING = 'UNICODE';
UPDATE pg_database SET datistemplate = TRUE WHERE datname = 'template1';