Following the demise of tropical cyclone Ruth off the central Queensland coast on 19 February 1980, the monsoon trough reformed with a weak low pressure system in the central Coral Sea on 20 February 1980. The low drifted west then turned southwest as it began deepening to reach cyclone intensity by 1800 UTC 21 February 1980.
Tropical cyclone Simon had a well organised spiralling inflow pattern on both Mackay and Gladstone weather radars as it approached the coast. There was a large well defined eye and the central pressure was estimated at 970 hPa as it made landfall about 50 km north of Yeppoon on the afternoon of 24 February 1980. However, with the eye half over land the cyclone altered direction through a right angle and moved back out to sea. For the next two and a half days the cyclone meandered southeast about 100 km off the Queensland coast while slowly intensifying further to achieve a central pressure of 960 hPa at 0600 UTC 26 February 1980.
Simon retained near-peak intensity for almost a day and at about 2200 UTC 26 February 1980 passed within 30 km of Sandy Cape which reported mean winds of 140 km/h and gusts to 170 km/h. Soon after, however, the cyclone accelerated away to the southeast and weakened steadily. It moved into the New Zealand area of responsibility at 1000 UTC 28 February 1980.
Simon caused shoreline erosion from Yeppoon to Bundaberg and some minor property damage from Byfield to Gladstone. The yacht Thisbe was blown ashore on Lady Elliot Island and a RAAF helicopter crashed on Fraser Island. No lives were lost.