summer months. In late summer there is a general northward shift of the circulation and the Gulf comes under the more direct influence of the equatorial low pressure belt. During the relatively constant summer conditions, the southerly position of the Azores-Bermuda cell brings about predominance of southeasterly winds. The winds tend to become more southerly in the northern part of the Gulf. Typical summer and winter circulation patterns are shown in Figs. 4 and 5. During winter, winds usually blow from easterly directions with fewer southerlies but more northerlies. Winds from west and southwest are

rare anytime during the year. Figure 6 depicts annual wind patterns from two localities along the Texas Coast, Galveston and Corpus

Air temperatures over the open Gulf exhibit narrower limits of variation both on a daily and seasonal basis. In July, average temperature over the center of the Gulf is about 85°F and gradually increases coastward to within 10°F of temperatures recorded at coastal localities. In January, average air temperatures over the Gulf are highest in the southeast, near Cuba and the Yucatan Peninsula, and decrease toward the north. East of Brownsville/Corpus Christi, January air temperatures over the open Gulf average about 65°F; at the Galveston-Mississippi Delta latitude, the temperature is about 60° F. The following table (Table 4) lists surface air temperatures from three localities along the Texas coast.

WIND: ARROWS FLY WITH THE WIND. LENGTH OF ARROW GIVES PERCENT OF TOTAL OBSERVATIONS TO
SIXTEEN POINTS OF THE COMPASS. BARBS SHOW FORCE ON BEAUFORT SCALE. FIGURE IN CENTER
OF CIRCLE GIVES PERCENTAGE OF LIGHT, VARIABLE WINGS.

0 10 20 30 40 50 60 70 80 90 100

SCALE OF WIND PERCENTAGES

Figure 4

Average Atmospheric Conditions over the Gulf of Mexico in July (from Leipper, 1954a).

WIND: ARROWS FLY WITH THE WIND. LENGTH OF ARROW GIVES PERCENT OF TOTAL OBSERVATIONS TO SIXTEEN
POINTS OF THE COMPASS. BARBS SHOW FORCE ON BEAUFORT SCALE FIGURE IN CENTER OF CIRCLE GIVES
PERCENTAGE OF LIGHT, VARIABLE WINDS.

Figure 5.

10

SCALE OF WIND PERCENTAGES

Average Atmospheric Conditions over the Gulf of Mexico in January (from Leipper, 1954a).

Figure 6. Annual wind patterns from two localities along the Texas coast. (Data source: U.S. Naval Weather Service Command, 1970). Numbers at the ends of the arrows indicate average velocity in knots; number at the center is the percentage occurrence of calms. Length of arrows indicate percentage occurrence of winds from that direction.

Year 81.1 62.4 71.8101 25