-what does it all mean?
The weight of air that makes up our atmosphere exerts a pressure on the surface of the earth i.e. atmospheric pressure, the more air above an area, the higher the pressure. Atmospheric pressure is also affected by altitude - atmospheric pressure is greater at sea level than on top of a mountain!
Barometric readings record atmospheric pressure taking into account variations in the differences in altitude.
Barometric pressure is an extremely useful weather forecasting tool. High pressure zones are generally associated with areas of fine weather, as opposed to Low pressure areas being associated with poor weather conditions and stronger winds.
Barometric pressure can be measured in;
Millibars (mb)
Millimeters (mm)
Inches (in)
This is the measure of the suns radiation reaching the earths surface. This irradiance includes both the direct component (from the sun ), and the reflected component ( from the sky).
It is measured in watts/m2
The suns energy reaches the earth as visible, infra red, and invisible UV rays. Exposure to UV rays can be harmful, causing numerous health problems. e.g. sun burn, skin cancer, skin aging and cataracts.
Readings of UV are in Index values
0 - 2 = Minimal Exposure
3 - 4 = Low exposure
4 - 6 = Moderate
7 - 9 = High
10+ = Very High
Always protect yourself from UV with sun screen creams, hats and suitable clothing!
The Heat Index uses the temperature and relative humidity to work out how hot the air actually feels.
When the humidity is low, the apparent temperature will also be lower than the actual air temperature, as perspiration evaporates rapidly to cool the body.
When humidity is high ( i.e. the air is saturated with water vapor) the apparent temperature feels higher than the actual air temperature as the body's perspiration evaporates more slowly.
remember 1 knot = 1.1 mph
1 Light air - ripples drifting conditions 1- 3 knots
2 Light breeze - small wavelets 4 - 6 knots
3 Gentle breeze - crests begin to break 7 - 10 knots
4 Moderate - small waves become larger, frequent white crests. 11 - 16 knots
5 Fresh breeze - moderate waves, many white crests 17 - 21 knots
6 Strong breeze - large waves, foam crests 22 - 27 knots
7 Near Gale - sea heaps, white foam, breaking waves blown in streaks 28 - 33 knots
8 Gale Force - moderately high waves, breaking crests, foam streaks 34 - 40 knots
9 Severe Gale - high waves, spray affects visibility 41 - 47 knots
10 Whole Gale - very high waves, long breaking crests 48 - 55 knots
11 Storm force - Wide spread damage 56 - 67 knots
12 Hurricane - Widespread destruction above 68 knots
