High temperatures are expected to reach the middle 80s on Monday, near 90 on St. Patrick's Day, and low 90s for the rest of the week. Record highs are likely to be broken from Tuesday through Friday, potentially jeopardizing Fresno's all-time hottest March temperature ever (91). The high pressure ridge responsible for this heat is particularly impressive as it occurs during the days of July when the sun is high in the sky. The first time Fresno reached 90 in March was on March 29, 1906.