It drifted southeastward, moving over northwestern Queensland on 10 March as a weak tropical cyclone, and subsequently turned to the southwest and later to the west.

Unfavourable wind shear, land interaction, and dry air prevented much restrengthening, and for several days Gillian was a weak tropical low.

Increased wind shear caused the cyclone to rapidly weaken, and both BoM and JTWC discontinued advisories on Gillian on 26 March.

[2] At 06:00 UTC on 8 March, the Bureau of Meteorology (BoM) office in Darwin began issuing warnings on the developing tropical low.

[3] Around that time, the United States Joint Typhoon Warning Center (JTWC), indicated the high potential for tropical cyclogenesis due to the increasingly organised circulation and convection.

[7] Early on 10 March, Gillian made landfall along the western Cape York Peninsula of Queensland,[8] after weakening below tropical cyclone status.

[1] A strengthening ridge to the south turned the storm to the southwest, bringing Gillian back over water; however, the circulation became poorly-defined and the convection decreased due to land interaction.

[13] On 14 March, the JTWC again assessed a high potential for Gillian redeveloping into a tropical cyclone, noting the appearance of a central dense overcast.

[15] Increasing wind shear again caused the storm to lose organisation early on 15 March,[16] prompting the BoM to downgrade Gillian to a tropical low.

[24] On 21 March, the convection reorganised due to a drop in wind shear,[25] and at 12:00 UTC that day, the BoM again upgraded Gillian to tropical cyclone status while the storm was about 380 km (240 mi) south-southeast of Jakarta.

[28] On 22 March, the storm passed just north of Christmas Island while Gillian was developing an eye; by that time, the 10 minute sustained winds had increased to 95 km/h (59 mph) within an environment favourable for continued strengthening.

[1][29] At 12:00 UTC on 22 March, the BoM upgraded the storm to a Category 3 on the Australian tropical cyclone intensity scale with 10 minute winds of 120 km/h (75 mph), the equivalent of a minimal hurricane;[29] a few hours later, the JTWC followed suit.

The heaviest rains, averaging 150 to 250 mm (5.9 to 9.8 in), fell along a corridor along southern part of the Cape York Peninsula from the Mitchell-Alice Rivers National Park to Cooktown.

[43] Though well to the north of Cyclone Gillian, the system's circulation drew moisture away from Riau western Indonesia, leaving behind fire-prone conditions.