1938 U.S. Hydrographic Office Map of the North Pacific Prevailing Winds

This is a March 1938 U.S. Navy Hydrographic Office aeronautic map of the North Pacific detailing prevailing winds. Wind roses indicate what the wind at the surface averaged over 100 hours. Boxes on the left and right sides provide average wind readings at 2,500 feet, 5,000 feet, and 10,000 feet above major cities of the Pacific Rim, including Shanghai, Hong Kong, Manila, Seattle, Los Angeles, and San Diego. Red lines trace air routes, including the famed China Clipper route from San Francisco to Hong Kong via Honolulu, Midway, Wake, Guam, and Manila. An inset in the upper left presents isobars and isotherms for March 1938 and an inset in the upper right details gales for the month of March. Explanatory information occupies most of the upper right.

Verso Content

A narrative of the March 1937 trailblazing Pan American flight from San Francisco to Auckland, New Zealand occupies the verso. This narrative details the flight, its waypoints, and the establishment of a Transpacific aviation route to Australasia, a landmark achievement in civilian aviation.

Publication History and Census

The U.S. Navy Hydrographic Office published Chart No. 1401 as early as 1895 on a monthly basis. Chart No. 1401a began being published on a monthly basis in January 1929. We have located cataloged examples of Chart No. 1401a dating from August 1931 (Issue No. 22) and April 1939 (Issue No. 124) along with the present example from March 1938.