Climate 
Climatic data for this area of the Pacific are available only from Midway 
Naval Station, 255 miles northwest of Lisianski* No significant difference is 
ilie 
expected between the general weather conditions of the two islands. s/Data used 
in this section are from a summary of the years 1955-1963 (NavSta Midway Fore¬ 
cast Handbook and Air Weather Service, [MATS] Climactic Center USAF). 
Climate in this region of the Pacific is marine, influenced by marine 
tropical or marine Pacific air masses depending upon the season. During 
summer the Pacific High becomes dominant, with the ridge line extending across 
the Pacific north of Midway. This places the region under the influence of 
easterlies with marine tropical and trade winds prevailing. During the winter, 
especially from November through January, the Aleutian thaw moves southward over 
the North Pacific, displacing the Pacific High before it. The Midway region is 
then affected by either marine pacific or marine tropical air, depending upon 
L 
the intensity of the Aleutian /ow and, or the Pacific High. 
Monthly maximum, minumum, and mean temperatures for a ten year period are 
shown in Figure ^V. The temperature variation shown is indicative of a marine 
environment. The mean annual range is l6°F. From December through April the 
means /y between 66°F and 69°F, and during the remainder of the year between 
° ^ o 
70 F and 8l F, the warmest months being July, August and September, and the 
coolest January, February and April. An inexplicable departure from the normal 
curve occurs in maximum, minimum and mean figures for April. A 37 degree 
n 0 0 
difference exists between the absolute high of 09 F and the absolute low of 52 F 
for this ten year period. 
Mean monthly precipitation and the number of days with measurable precipi¬ 
tation are tabulated in Figure V| # Rain or drizzle most frequently occur •brot/w 
