Dry Season Subsides, Wet Season Arrives in Hawai‘i

Rainfall totals soared across much of West Hawai‘i throughout the summer. PC: Pixabay

Hawai‘i’s dry season wasn’t terribly dry, at least not early on, according to information released by the National Oceanic and Atmospheric Administration (NOAA) Friday.

Most locations had near-average or below-average rainfall between May and September 2020, but most areas started the dry season drought-free due to wet conditions early in the year, with the exception of Maui County.

Eventually, however, drought spread to all counties, reaching extreme levels in Maui County and leading to brush fire red flag alerts on the leeward side of all islands in recent weeks. The lack of moisture also had an explicit impact on ranching operations statewide, according to NOAA.

All told, the 2020 dry season ended up being the 11th driest over the last 30 years. For reference, 2003 was the driest and 2015 was the wettest.

Outlook for the wet season (October 2020 through April 2021)

NOAA’s Climate Prediction Center indicates that current La Nina conditions are likely to continue through spring 2021.

The climate model consensus favors above-average rainfall through the wet season, with large-scale, wetter than average conditions particularly from December 2020 through April 2021.

Stronger La Nina events can have a higher than normal trade wind frequency, which will focus rainfall on windward areas. Weaker La Nina events tend to have more weather systems that produce significant leeward rainfall.

Projections indicate that drought recovery is more likely on the smaller islands (Kaua‘i to Molokai), and over the windward slopes of Maui and the Big Island. There is the possibility for drought conditions to continue through the wet season, especially over the leeward areas of Maui and the Big Island.