Rain and thunderstorms on Oahu and Kauai Saturday hindered observations in the last of three Ocean Counts to be held this year by the Hawaiian Islands Humpback Whale National Marine Sanctuary.

Officials canceled viewing at multiple shoreline sites on the two islands due to the poor weather, while conditions were clear on Hawaii island, according to a NOAA news release.

More than 442 volunteers gathered data from 43 sites statewide. The busiest period of the day for whale activity was between 11 and 11:15 a.m., with a total of 34 whale sightings recorded, the release said.

Humpback whales migrate to Hawaiian waters each winter to mate, calve and nurse their young. The sanctuary holds the Ocean Count annually during peak whale season to promote public awareness about the animals, the sanctuary and shore-based whale-watching opportunities, the release said.

Participants tally whale sightings and document surface behavior, such as tail and head slaps, blows, dives and breaches, during the survey to provide a snapshot of humpback whale activity from the shoreline.

More than 557 volunteers participated in the first session Jan. 27, reporting from 46 sites statewide. The 10:30 to 10:45 a.m. time period was the busiest, with 172 whale sightings.

During the Feb. 24 survey, 649 volunteers gathered data from 44 sites. A total of 135 whale sightings were seen during the 10 to 10:15 a.m. period, the most of any time period throughout the day’s count.

The Hawaiian Islands Humpback Whale National Marine Sanctuary is administered by NOAA’s Office of National Marine Sanctuaries and the state Department of Land and Natural Resources. For more information, visit hawaiihumpbackwhale.noaa.gov.