Diego Garcia Island • Statistics for March

March: Peak Offshore Flow Before the Trade Wind Monsoon

March marks the statistical peak of favourable winds: ideal for surfing 49 percent of the time, the highest of any month. The wind direction is firmly in the WSW-W-WNW corridor, with W (15.0%) and WNW (16.5%) again carrying the bulk of the offshore flow. The average swell height rises just slightly to around 5-6ft (1.7m), and the period lengthens to 11.7s, so there is real power in the water. Direction-wise, the swell windows are dominated by S (38.2%) and SSE (31.7%), with SSW at 16.6%; true westerly swell shrinks to WSW (2.0%) and W (0.8%). The result is a month with plenty of rideable long-period swell, especially in the 5-8ft (1.5-2.5m) range, but surflines are almost always better described as fun-sized southern groundswell held open by offshore winds rather than classic west-swell perfection. Precipitation drops to 5.87mm/day, water temperature peaks at 29.3°C, and air temperatures average 27.9°C, so it is warm, humid and occasionally glassy.