What to expect transiting the Indian Ocean during June

June Pilot Chart

NOAA Pilot Chart Average Surface Pressure and Tropical Cyclone tracks over Indian Ocean in June


South Indian Ocean

A ridge of high pressure normally extends from South Africa eastward to the west coast of Australia, mainly between 25-30 south latitudes. Southward of about 35 south latitude, westerly winds prevail averaging forces 5-6 (17-27 knots) with significant wave heights generally 2-3 meters.  Northward of the prevailing ridge, winds tend to be from the southeast averaging force 4-5 (11-21 knots) with waves mostly 1.5-2 meters, becoming southeast to south forces 3-4 (7-16 knots), waves 0.5-1 meter nearing the equator. 

The risk for encountering gale force (BF8/34kt) or higher winds is 10% or less from the equator to about 35 S latitude then increases from 10% to 26% southward of 35 S.  The risk of encountering waves of 12 feet (3.7 meters) or higher is 30-40% from about 40S southward, diminishing to  20-30% near 30 S and generally 15% or less north of 20 S latitude. 

North Indian Ocean 

Arabian Sea

The Southwest Monsoon establishes itself in June and the frequency of gales increases rapidly over the western half of the Arabian Sea reaching over 10% with the highest risk near 14 N 57 E.

June Monsoon

Monsoon over Arabian Sea during June

The risk of encountering waves of 12 feet (3.7 meters) or more increases over this area from less than 10% in May to as high as 40% or more in June. In the same area there is also a 5% risk of encountering waves of at least 20 feet (about 6 meters). 

Bay of Bengal

Generally a southwest monsoon prevails in June, averaging forces 4-5 (11-21 knots) with waves mostly 1.5-2 meters.

Tropical Cyclones

Cooler temperatures in the southern hemisphere in June reduce the risk for tropical cyclone development to less than 1 every decade. Over the North Indian Ocean there is a 70% risk for tropical cyclone development and mostly confined to the eastern Arabian Sea and Bay of Bengal.  

June IO Pilot Chart

NOAA Atlas of Pilot Charts for Indian Ocean in June


About Fred Pickhardt

I am a marine meteorologist and sailed briefly with American Export Lines in the Far East trade after graduating from State University of New York Maritime College. I have extensive experience in weather analysis, weather forecasting, optimum ship routing, vessel performance evaluations and forensic weather event reconstructions. I founded Ocean Weather Services and as Owner and Chief Consultant currently provide optimum ship routing services and forensic marine weather reports to the maritime industry.
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