It may come as no surprise that the weather is very complex and variable.. . . . Belize comes under the influence of about five different weather patterns at different times of the year.

There are the ITCZ flare-ups that can bring heavy rains, between around June to September. . . . .We also get the so called "Tropical Waves" which bring wet and windy conditions in from the Caribbean. . . . .We get Cold Fronts coming down from the North, mainly between late October, through into early April. . . . .

It may appear odd, but typically, for much of the year, our prevailing wind is from the SW, that is from the Pacific, over Guatemala, OK that is a higher level wind, not the surface wind, except in the early morning, and sometimes late at night, which has been called the "Tiger Wind" by some old Belizeans, because it appears to start up in the evening, coming down from the Mountains.

We also get Weather swell-ups, moving up from the South, bringing rain and Thunder storms. . . . .Not forgetting that we are in the Hurricane Zone. . . . In the early part of the Year, April, May, Tropical storms can sometimes come from the Pacific, over Central America and hit Belize, such as Arthur, first called Alma, when it was in the Pacific. . . . The first time a Tropical Storm was named when it was already on Land, that was on Belize : Tropical Storm Arthur in May/Jun 2008. . . . For the main Hurricane Season, Tropical Storms usually come out from the Atlantic, off Africa. . . .But late in the season, they can develop right in our back door, that is in the southern Caribbean, even just off the Central American coast.

Belize weather, is very variable and can be unpredictable, even with all the modern satellite and radar aids. . . . . Some years, we can have serious wet weather sitting on Belize, dropping rain for hours and hours. . . . Just last year 27 May 2013, we had 156mm ( >6” ) in just one day. . . That was a record for at least 10 years or longer. . . . .Even 100mm ( 4” ) is not often exceeded on a single day. . . . But then some times, we can get very heavy Rain for just an hour or two, or continuos light rain for hours and hours, even days on end, but this is not common. . . . With the typical Dry Season from around March, through to the last week in May. . . .There is usually some rain during this period, a day average of about 15mm ( ½”) but sometimes we get no rain for weeks, even months occasionally, such as early this year 2014. . . . Most of March and all of April this year. . . .But surprisingly, heavy rains in early May. . . . As I say, we have unpredictable weather here.

Rainfall is typically much more variable, being up to 2 times higher in the South and only half Belmopan rain, up in the North.

We have had Temperatures, way down in the freezing 50°F’s ( 12°C ), night after night, but they don’t often get below 65°F ( 18°C ) . . . But these are random, at any time between November to March. . . . During March to May, I have seen temperatures up to 106°F ( 41°C ) . . . But over 100°F ( 38°C ) fairly often. . . . The mid-day temperatures can typically be around the 95° F ( 35°C ) mark, many days of that hot, dry period.

The typical Winter Night time Temperatures are variable between 65-75°F ( 18-24°C ) with day Temperatures of 75-85°F ( 24-30°C ) . . . . Summer night time Temperatures are usually very fixed on 77°F ( 25°C ) with day time Temperatures around the 85-95°F ( 30-35°C ) range.

These Temperature figures are for Central Belize, Belmopan in particular. . . . .The Coastal Day time temperatures are usually a little cooler due to the sea breezes. . . . The Mountain day and particularly night time temperatures are cooler than Belmopan. . . . . Belmopan being about 50 miles ( 80 km ) inland and approximately 260 ft ( 80 m ) above sea level.

Click image for larger version

ITCZ – ( InterTropical Convergence Zone ) : http://en.wikipedia.org/wiki/Intertropical_Convergence_Zone

ITCZ is rather more complicated than Wikipedia makes it out to be, but there is good information there.. .. Basically Hot air, as heated by the Tropical Sun, rises due to the heating, and rises rapidly. . .. When it gets to a height that causes it to condense into cloud. ... . The very action of condensing from dry air holding moisture, to cloud, where the water has condensed out of the air, releases energy, which heats up that air mass, so it rises even more rapidly. .. ..Don’t think that this means all that air is hot, it is not. .. . . .It is continually cooling as it rises, but it is hotter than the other around, that it is rising in. . .. .These ITCZ swellings, can and usually do, go up to considerable heights. ...Those Red areas on those satellite pictures I send out, indicate the heights. ... Actually they are the temperatures. .. .Oddly, the Redder, the colder, but that actually translates to height.

The reason they call these ITCZ is because they mainly occur in the Tropics, along the equator, or Sun’s Zenith ... . No, not the physical Equator, but the effective equator as the Sun sees it. . ..So the band of ITCZ moves up North, during our Summer months, often well north of Belize, and South, well south of Belize, even South of Panama, during our Winter months. . .. . .Right now, September, they are starting to go South of us.

The Wikipedia article rather over simplifies all this. . .It sort of assumes that ITCZ is fairly constant along this Sun’s equator I mention, so when it goes up and up to great heights, it has no where to go, so they have to go outwards, which means that it collapses Northwards of the ITCZ line and Southwards of the ITCZ line, thus forming those vertical Looks as shown in that Wikipedia article. . . . Looks like Wikipedia have realized they over simplified and have removed part of what I was looking for, namely the Hadley Cell diagrams. . . . ..Found what I was trying to show Jet Streams . . . .This shows the Vertical movements of the Hadley cell caused by ITCZ activity and how the high air flows outwards, resulting in rain where the tops collapse.

Hadley Cell & Jet Streams although this drawing includes the Ferrel Cell and Polar Cell as well.

At least, this is the principle. . . ..In practice, the ITCZ activity is far more complicated and broken up. .. .But typically form in the late afternoon and evening, after the Land or Sea has warmed up from strong Tropical Sunlight. . ..The can be very large connected areas or much smaller localised areas, but they typically go through their cycle in just hours, so hard to predict the results of them, regarding rain.

The more common, day time Cumulus Clouds we frequently get, which tend to build up as the day goes on, giving those puffy white clouds, a caused in a similar, but much smaller way. . . . .Again as the day warms up, the air heated from the land or sea, rises up to a few thousand feet, where the air is cooler, so the moisture in the rising air cools and condenses into clouds, usually with fairly flat bottoms to them. . . . .These don’t usually bring rain, unless they get too big and heavy. . . . Good details in the Wikipedia article on Cumulus Clouds . . . When they get heavy with moisture, the get dark and are called Cumulonimbus Clouds.

Cold Fronts coming down from the North are very different. . . . These Cold Fronts that come down over the USA during the Winter months, do not normally cross over Belize, but we do often get side swiped by them, which can bring us significant rain. . ...A normal cold Front passing over can usually be detected by a line of cloud, then rain crossing over, followed by clear blue skies and no rain behind, but this does not usually happen in Belize, as I say, we usually get side swiped, so we often get long, usually light periods of rain from them... .. .Because Cold Fronts form a Wedge, moving over the ground, with the cold air close to the ground, you can often feel the cool air well before the charts show the Cold Front line to be.

Thunder Storms are usually caused by two different air masses, rubbing against each other. . .. This can either be an upper air movement in a different direction to the lower air movement, or it can be due to vertical air movement in Large Cumulus clouds, when they are seriously developing, that can be afternoon and evening. . . .. There as Thunder storms caused by two different direction air masses can occur at any time of the day or night. . .. .Thunder being caused by the very rapid expansion of air, resulting from an Electrical Lightning Strike. . . . .these can be between clouds, or from clouds to Ground. . .. .Typically the lower part of such clouds become Negatively charged and the upper parts become positively charged.. . . ..These ground Lightning strikes involve very large, short-duration discharge currents. 90% of all strikes exceed 8,000 A, and 1% exceed 200,000 A. . . The rise time of the current pulse is very short, typically 200,000 A/µs. . . . . There are usually multiple strikes at any one time, so fast, they look like a single strike, the first might not be bright, but having established a path, the next strike or few can be very powerful. . ... The chance of anyone being directly hit by Lightning is very, very slim. .. .It is usually small side whiskers that sometimes hit people. .. .But high surge currents in the ground can be very dangerous... . .So you should always seek shelter in a good building or metal roofed vehicle, keeping away from the windows. . . . If you are caught out in the open, with no shelter to run to, then keep your feet as close together as possible, or if running, run with only one foot in contact with the ground at any one time, the other foot in the air, do not touch the ground with a hand or any other part of the body.

Hugh Leyton