QUERY:
INSERT INTO bdarduino.tbmedia (estacao, temp, umid, vent)
SELECT estacao, AVG (sensor1) AS temp, AVG (sensor2) AS umid, AVG (sensor3) AS vent from bdarduino.tbsensores
where datahora between now() - INTERVAL 1 DAY and now()
GROUP BY estacao;

SQL das tabelas:
CREATE TABLE tbsensores (
id int(11) NOT NULL AUTO_INCREMENT,
estacao varchar(35) CHARACTER SET utf8 NOT NULL DEFAULT ‘’,
sensor1 varchar(15) CHARACTER SET utf8 NOT NULL,
sensor2 varchar(15) CHARACTER SET utf8 NOT NULL,
sensor3 varchar(15) CHARACTER SET utf8 NOT NULL,
datahora datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (id)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=latin1;

CREATE TABLE tbmedia (
Id int(11) NOT NULL AUTO_INCREMENT,
estacao varchar(255) DEFAULT NULL,
temp varchar(255) DEFAULT NULL,
umid varchar(255) DEFAULT NULL,
vent varchar(255) DEFAULT NULL,
tpResultado varchar(255) DEFAULT NULL,
datahora timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (Id)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;