Cyclone Nargis (also known as Very Severe Cyclonic Storm Nargis) was a strong tropical cyclone that caused the deadliest natural disaster in the recorded history of Myanmar (also known as Burma). The cyclone made landfall in the country on May 2, 2008, causing catastrophic destruction and at least 78,000 fatalities with a further 56,000 people still missing. However, Labutta Township alone was reported to have 80,000 dead and some have estimated the death toll may be well over 100,000.

Nargis is the deadliest named cyclone in the North Indian Ocean Basin, as well as the second deadliest named cyclone of all time, behind Typhoon Nina. Including unnamed storms, Nargis is the 8th deadliest cyclone of all time. Nargis was the first tropical cyclone to strike the country since Cyclone Mala made landfall in 2006.

The cyclone name "Nargis" is an Urdu word meaning daffodil. The first named storm of the 2008 North Indian Ocean cyclone season, Nargis developed on April 27 in the central area of Bay of Bengal. Initially it tracked slowly northwestward and, encountering favorable conditions, it quickly strengthened. Dry air weakened the cyclone on April 29, though after beginning a steady eastward motion Nargis rapidly intensified to attain peak winds of at least 165 km/h (105 mph) on May 2; the Joint Typhoon Warning Center assessed peak winds of 215 km/h (135 mph). The cyclone moved ashore in the Ayeyarwady Division of Myanmar near peak intensity and, after passing near the major city of Yangon (Rangoon), the storm gradually weakened until dissipating near the border of Myanmar and Thailand.

In the last week of April 2008, an area of deep convection and concern persisted near a low-level circulation in the Bay of Bengal about 1150 km (715 mi) east-southeast of Chennai, India. With good outflow and low wind shear, the system slowly organized as its circulation consolidated. At 0300 UTC on April 27, the India Meteorological Department (IMD) classified the system as a depression, and nine hours later the system intensified into a deep depression. At the same time, the Joint Typhoon Warning Center classified it as Tropical Cyclone. With a ridge to its north, the system tracked slowly north-northwestward as banding features improved. At 0000 UTC, 5:30 AM Indian Standard Time, on April 28, the IMD upgraded the system to Cyclonic Storm Nargis while it was located about 550 km (340 mi) east of Chennai, India.

On April 28 Nargis became nearly stationary while located between ridges to its northwest and southeast. That day the JTWC upgraded the storm to cyclone status, or the equivalence of a minimal hurricane on the Saffir-Simpson hurricane scale. Around the same time, the IMD upgraded Nargis to a severe cyclonic storm. The cyclone developed a concentric eye feature, which is an eyewall outside the inner dominant eyewall, with warm waters aiding in further intensification. Early on April 29, the JTWC estimated Nargis reached winds of 160 km/h (100 mph), and at the same time the IMD classified the system as a very severe cyclonic storm. Initially, the cyclone was forecast to strike Bangladesh or southeastern India. Subsequently, the cyclone became disorganized and weakened due to subsidence and drier air; as a result, deep convection near the center markedly decreased. At the same time, the storm began a motion to the northeast around the periphery of a ridge to its southeast. The circulation remained strong despite the diminishing convection, though satellite intensity estimates using the Dvorak technique indicated the cyclone could have weakened to tropical storm status. By late on April 29, convection had begun to rebuild, though immediate restrengthening was prevented by increased wind shear.

Satellite image of Nargis near landfallOn May 1, after turning nearly due eastward, Cyclone Nargis began rapidly intensifying, due to greatly improved outflow in association with an approaching upper-level trough. Strengthening continued as it developed a well-defined eye with a diameter of 19 km (12 mi), and early on May 2 the JTWC estimated the cyclone reached peak winds of 215 km/h (135 mph) as it approached the coast of Burma. At the same time, the IMD assessed Nargis as attaining peak winds of 165 km/h (105 mph).  Around 1200 UTC on May 2, Cyclone Nargis made landfall in the Ayeyarwady Division of Burma. The storm gradually weakened over land, with its proximity to the Andaman Sea preventing rapid weakening. Its track turned to the northeast due to the approach of a mid-latitude trough to its northwest, passing just north of Yangon with winds of 130 km/h (80 mph). Early on May 3 the IMD issued its final advisory on the storm. It quickly weakened after turning to the northeast toward the rugged terrain near the Myanmar-Thailand border, and after deteriorating to minimal tropical storm status, the JTWC issued its last advisory on Nargis.