DOHA: The prevailing winds during July are mainly north north-westerly with a daily mean speed of 8.3 knots (15.3 kilometres per hour). These winds, known locally as Al Bareh, are characterised by a low speed during the night (over land only), which increases gradually after sunrise to reach maximum strength around noon.

The analysis of July Shamal days, from 1976 to 2008, indicates there are four spells during the month: July 1-4, July 7-13, July 17-18, and July 28-29.

These spells are marked by the most frequent occurrence of the Shamal winds in a single day. The summer Shamal has longer duration than the winter Shamal. These winds result in poor visibility and wind shear over land and the high seas. A previous study about the summer Shamal indicated that the lower level winds are most prevalent in July.

Although July is the hottest month in the year with a monthly mean temperature of 41.8 degrees Celsius, the number of days with extreme temperatures is less compared to June, the second hottest month of the year.

The average maximum and minimum temperatures during the month are 41.8 degrees Celsius and 29.9 degrees Celsius, respectively. The analysis shows that the first two-third of the month is warmer than the remaining period, and the first five days are the second hottest period in the year after the last five days in June.

The data shows below-normal temperatures during July from 1962 to 1993, after which the minimum temperature has remained above normal with the exception of three years.

Relative humidity normally starts to increase slightly during the second half of July as winds with an easterly component are dominant during the period. The lowest relative humidity on any day can be between four and 15 percent with winds having a westerly component and generally reported around noon, when the temperature is at its peak. The highest values may reach 89-100 percent, mostly with winds having an easterly component and reported at dawn, when the temperature is at

its lowest.

The daily mean sea surface temperature recorded at Doha Port (1979-1989) at 6am during July was 32.4 degrees Celsius. The highest maximum temperature was 36.2 degrees Celsius, reported in 1987, and the lowest minimum was 27 degrees Celsius, reported in 1986.

THE PENINSULA