The next day the Joint Typhoon Warning Center issued a tropical cyclone formation alert on the developing disturbance.

After reaching its peak intensity, Rammasun weakened and was downgraded to severe tropical storm on May 12, before the JTWC declared it extratropical and issued their final advisory.

In all, the typhoon killed four people, injured 40 others and caused $9.6 million (2008 USD) worth of damage in both the Philippines and Japan.

[1] Early on May 6, the JTWC upgraded the disturbances chances of forming into a tropical cyclone within 24 hours to "fair", as the low level circulation center had consolidated further.

[3] Early the next day both the Japan Meteorological Agency (JMA) and the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) designated the tropical disturbance as a tropical depression with PAGASA assigning the local name of Butchoy to the depression.

[28][29] The JMA continued to issue advisories on severe tropical storm Rammasun until early the next day when they downgraded it to an extratropical low.

However, they did warn that the cyclone was expected to enhance the southwest monsoon and bring rain over Central and Southern Luzon, Visayas and Mindanao.

[34] Later that day, a boat carrying 17 people capsized due to rough seas produced by the typhoon.

[36] Strong winds also downed numerous trees, one of which, measured at 60 centimetres (2.0 ft) in diameter, fell on three forest guards, killing two and critically injuring the other.

[37] In Jaro, Iloilo City, a swollen river overflowed its banks, inundating the district.

[34][39][40] On May 12, the Japan Meteorological Agency issued warnings for the Tokyo area as Rammasun was forecast to make landfall near the city.

[41] As Rammasun became extratropical, the storm brushed the Japanese coastline on May 13, producing winds gusting up to 85 km/h (53 mph) and high waves for several hours.