JULY is dependably undependable. So far this year, tile month in question has been decidedly on the cool side, yet 330 years ago on this day, on July 5th, 1666, Samuel Pepys: was able to record in his famous diary: "Extremely hot oranges ripening in the open at Hackney." And this was in the middle of the so called Little Ice Age, when the climate in these parts was, in general, much less amenable than it is today.
Part of the problem, of course, is that Ireland, in common with most countries in the "temperate" latitudes, suffers from a certain blurring of the seasons. The Indian monsoons, for instance, separate the year into two unmistakably different parts, a wet season with moist south westerly winds, and a dry one with cool north easterlies.
But the differences in character in the Irish seasons are of degree rather than of kind summer depressions are fewer and less vigorous than their winter counterparts, and usually travel eastwards at a higher latitude, nearer to Iceland than to us.
But the summer norm for Ireland is still a changeable regime, dictated by the generally westerly pattern of our winds. Indeed a spell of warm sunny weather in Ireland is an anomaly, albeit a fairly frequent one.
It is common for the earlier part of June to provide such an anomaly. Some meteorologists; however, have noted that the last week or so of that month often sees a return to predominantly westerly winds and unsettled weather.
They put the change down to the fact that the enhanced power of the summer sun around this time often results" in a rise in pressure over the Atlantic, and a corresponding fall over the Continent, almost like the sea breeze effect on a continental scale.
The consequence of this change in the pressure pattern is a more westerly flow of wind over Ireland, a moist air flow which brings with it more cloud, higher relative humidity, and usually an increase in rainfall.
The change is sometimes referred to as the onset of the "European monsoon", an analogy with the very much more dramatic phenomenon which is a regular feature of the climate of South East Asia.
Some meteorologists also believe that Irish summers very often settle down by about mid July into some persistent character; either mostly wet and windy, or mostly dry and sunny.
Once the general character of the weather has become established in this way, they say, it tends to persist until near the end of August. If this be so, we should watch the weather closely over the next week or so to see what the rest of summer 1996 may have in store.