The average temperature in Ontario, CA the average temperature is 36.7 degrees in summer, with precipitation around 1.4 mm , Augusta, ME's temperatures reach 36.23 during the hot season, with 12.0 average of rain rate . In winter, however, weather indicators show around -3.8 degrees in Augusta, ME, compared to the -0.46 average degrees reported in Ontario, CA. During the winter period, Ontario, CA can register 3.0 mm precipitation, while Augusta, ME have an average of 6.0 mm rain level.