Tropical cyclone Monica was the first cyclone to affect the Eastern Australian region in the 1984-85 season. Monica formed about 0300 UTC on 27 December 1984 near 16.5°S, 152.0°E from a tropical low which had been embedded in the ITCZ for about 36 hours. The central pressure at this time was 990 hPa. Monica took an overall southeasterly track, starting at 14.4°S, 148.3°E at 2100 UTC 25 December 1984. It slowly deepened to reach maximum intensity at about 1800 UTC 27 December with a central pressure of 982 hPa. The cyclone was then at 17.4°S, 153.7°E with estimated maximum winds of 85 km/h. Subsequently the southeasterly track continued, but the cyclone began to weaken. Monica moved into the Fiji RSMC area of responsibility at 1200 UTC 28 December near 21.5°S, 160.0°E with a central pressure of 988 hPa. Monica lost its cyclonic intensity about 36 hours later when it was near 29°S, 163°"E. The maximum reported wind was 74 km/h at 0300 UTC 28 December from a ship at 21.3°S, 154.2°E.
No reports of damage were received.