Late in the nineteenth century, Sir Albert Ellis of New Zealand discovered that the rocks found on Nauru (0.26ºS, 165.55ºE) and Ocean (now Banaba) Islands (0.53ºS, 169.35ºE) contained large amounts of high-quality phosphate. Mining soon began, with the phosphate shipped out from ports located on the west side of the islands. These ports were closed to shipping during times of strong westerlies. Records kept by the British Phosphate Commission and its successors provide an almost 100-year long monthly timeseries of when strong near-surface westerlies occurred at these two islands, as well as monthly rainfall at these two remote islands. These records will be augmented by monthly precipitation records from Tarawa (1.36ºN, 172.92ºE) dating back to 1926 and by modern TAO buoy records.

The number of days per year during which the ports were closed due to bad weather is highest (lowest) during years when the SOI was negative (positive). This is consistent with results from late twentieth century surface observations and analyses, which show that the annual frequency of westerly wind bursts is negatively correlated with the SOI. Results of a lagged correlation analysis between monthly values of the SOI, port closings, and west Pacific precipitation will be presented, as will a more modern analysis of the relationship between the SOI, strong equatorial westerlies, and precipitation over the Warm Pool. Patterns of variability seen in the historical proxy data will be compared to those seen in data from the later portion of the twentieth century.