Intense display: The Hong Kong Observatory's sensors detected 10,000 lightning strikes between 10pm and midnight July 20, highlighting a month of atypical weather.

July was wetter than usual with several huge thunderstorms, yet it was also hotter and sunnier seeing its second-hottest day on record.

The Hong Kong Observatory said the month's mean temperature was 29.1 degrees, 0.3 degrees higher than normal, with 13.4 hours of sunshine than usual at 244.5 hours. Rainfall at 360.4mm was 36.9mm above normal. And accumulated rainfall for the year was 1,872.9mm, 42% above normal.

A trough of low pressure brought showery weather to Hong Kong on July 1. Seasonably-fine weather prevailed for the next five days with temperatures reaching 33 degrees July 4, 5 and 6. Storms occurred July 7 and the weather remained unstable for the next two days before fining up July 10.

3-day heat wave

Typhoon Haitang over the western North Pacific brought very hot conditions to Hong Kong July 17 to 20 as intensely-heated inland air pushed temperatures up to 35.4 degrees, July's second-highest reading ever.

July 20 saw thunderstorms, with the observatory's sensors detecting 10,000 lightning strikes between 10pm and midnight, reportedly causing 29 power failures mainly in Kowloon and the New Territories.

The squalls continued the next day with winds gusting to more than 100kph at Black Point and hail being reported on Tsing Yi. There were further showers and storms on July 22, sunny periods July 23 and isolated showers July 24.

Weather was then mainly fine until Tropical Storm Washi formed over the northern part of the South China Sea and brought squally showers to Hong Kong on July 29, with gusts exceeding 100kph on Cheung Chau. The thundery showers continued for the last two days of the month.