The Joint Typhoon Warning Center (JTWC) of the United States and other national meteorological services, including Météo-France at Réunion, also monitored the basin during the season.

[1] The forecasts took into account various factors, including the latest neutral to weak La Niña conditions that had been observed in the tropical Pacific Ocean.

[1] On 8 August, TCWC Perth started to monitor a tropical low located approximately 850 km (530 mi) to the west-northwest of the Cocos Islands, on the 90th meridian east—the western edge of the BOM's area of responsibility.

[3][4] The tropical low moved in a west-southwesterly direction[3] and attained 35 km/h (20 mph) sustained winds south of the circulation center,[5] and a minimum barometric pressure of 1005 hPa (29.68 inHg).

[8] The JTWC, however, issued a Tropical Cyclone Formation Alert early on 27 November, stating that satellite imagery depicted flaring convection near its center.

[10] Winds from the cyclone also blew ash from nearby Mount Agung on Bali westwards to its popular beaches and far eastern Java.

[13] Although Cempaka never made landfall, the rainfall from the storm caused severe flooding and landslides across the southern half of Java and Bali, killing at least 41 people and destroying many homes and businesses.

[19] Best track reanalysis by the Bureau of Meteorology concluded that Dahlia reached tropical cyclone intensity as a Category 2, with sustained winds of 50 knots on 1 December and a minimum barometric pressure of 985 hPa.

[20] Dahlia maintained its intensity for several hours until the storm moved southeastwards and began to rapidly weaken on 2 December as it interacted with Ex-Tropical Cyclone Cempaka.

[30] A tropical low developed over the Joseph Bonaparte Gulf on 7 January 2018, and moved over the Kimberley region of Western Australia the next day.

In a 24-hour span, 439 mm (17.3 in) of rain fell across Broome, Western Australia, with flood waters in some areas reaching depths of 1.2 to 1.5 m (4 to 5 ft).

[citation needed] The effects of the low were considered substantially worse than Hilda and Joyce, tropical cyclones that affected the same region earlier in the season.

On 11 March, satellite imagery showed that atmospheric convection was persisting around a low-level circulation centre, that had developed on 160°E to the southwest of the Solomon Islands.

[34] On 11 March, the Fiji Meteorological Service reported that Tropical Disturbance 10F had developed about 85 km (55 mi) to the southwest of Rennell and Bellona Province of the Solomon Islands.

[39] Late the same day, the JTWC assessed the system to be producing gale-force winds, and upgraded it to tropical storm status on the Saffir–Simpson scale.

[40] As a result of the further deteriorating atmospheric conditions and cooling sea surface temperatures due to movement away from warm equatorial waters, Linda weakened to a subtropical low during mid-morning on 14 March, having spent fewer than 24 hours as a cyclone.

[38] The remnant low transitioned to a south-southeasterly track and continued to decay while travelling roughly parallel to the coastline, finally dissipating on 16 March.

[40] Ex-Tropical Cyclone Linda passed within about 300 km (190 mi) of Fraser Island at its closest approach to Australia, and produced large waves and swell which were experienced on exposed southern Queensland beaches.

[41] Sustained gale-force winds were recorded on the Australian mainland at Double Island Point on 14 March, with gusts up to 85 km/h (55 mph).

[42] On 14 March, the Australian Bureau of Meteorology issued cyclone warnings for Darwin, the Tiwi Islands and parts of the northwest Top End.

[citation needed]On the afternoon of 19 March, the Bureau of Meteorology reported on the development of a weak tropical low in the Torres Strait, north of Thursday Island.

Within the next couple of days, Nora intensified into a Category 3 Severe Tropical Cyclone, before making landfall on the Top End at that intensity.

[50] Tracking generally southwards along the western periphery of a near-equatoral ridge,[51] Iris remained weak with an exposed low-level circulation centre, which resulted in the final warning from the JTWC being issued at 09:00 UTC on 27 March, as colder sea surface temperatures further eroded the fully sheared system.

[54] The JTWC issued a Tropical Cyclone Formation Alert for Iris again on 1 April, due to the increasing amounts of persistent convection and improving low-level banding.

[55][56] Both the BoM and the JTWC reported that Iris had redeveloped into a tropical cyclone at around 10:00 AEST (00:00 UTC) on 2 April, supported by Dvorak technique estimates as well as sustained gales recorded by the automatic weather station at Flinders Reef.

[61] Early on 3 April, Iris resumed its south-southeastward track and turned eastward;[62] at the same time, the low-level circulation centre became partially exposed, with deep convection only persisting over the southern periphery of the storm, showing that the intensification had stopped.

[72] The tropical low moved in a general westward direction for several days until it was last monitored by TCWC Perth on 19 January.

[73] On 27 January, TCWC Brisbane began monitoring on a tropical low-pressure system that was located to the south of the Solomon Islands.

The TCWC in Jakarta, operated by the Indonesian Agency for Meteorology, Climatology and Geophysics, monitors tropical cyclones from the Equator to 11°S and between the longitudes 90°E and 145°E.