Sponsors
Foto Album
The Weather Now!
Radio Amateur
Historical Weather Measurements for Piraeus and Athens
Pireas weather station is privately owned and operated, is not affiliated with the City of Piraeus, and the data on this site should not be used to base important decisions that could result in harm to people or property. Located at a private residence in Piraeus in the area of Kalipoli one km. Northwest from Piraeus downtown, 500 meters from the main Port of Piraeus and 300 meters inland from Piraiki – the sea of Saronic golf.-
Pireas weather Station locate:
Latitude: 37.92.01 – Longitude: 23.63.10 and 68 meters above the sea level.
These plots are from our station’s archives
Rain and Measurements
1) All liquid or solid phase aqueous particles that originate in theatmosphere and fall to the earth’s surface.
2) The amount, usually expressed in millimeters or inches of liquid water depth, of the water substance that has fallen at a given point over a specified period of time.
As this is usually measured in a fixed rain gauge, small amounts of dew, frost,rime, etc., may be included in the total. The more common term rainfall is also used in this total sense to include not only amounts of rain, but also the water equivalents of frozen precipitation.
For obvious reasons, precipitation is the preferred general term.
The only other form of liquid precipitation, drizzle, is to be distinguished from rain in that drizzle drops are generally less than 0.5 mm in diameter, are very much more numerous, and reduce visibility much more than does light rain. For observing purposes, the intensity of rainfall at any given time and place may be classified as:
1) light, the rate of fall varying between a trace and 0.25 cm per hour, the maximum rate of fall being no more than 0.025 cm in six minutes;
2) moderate, from 0.26 to 0.76 cm per hour, the maximum rate of fall being no more than 0.076 cm in six minutes;
3) heavy, over 0.76 cm per hour or more than 0.076 cm in six minutes.
When rain gauge measurements are not readily available to determine the rainfall intensity, estimates may be made according to a descriptive system set forth in observing manuals.
A more accurate term would be precipitation or precipitation amount.
However, the broad use of “rainfall” is firmly established in meteorology, especially in hydrologic and climatological literature.
Its best utilization would confine it to liquid precipitation, and so would provide a distinction between precipitation immediately accessible to soil and streams and that delayed in storage as snow or ice on the earth’s surface.
For weather-observing purposes, the intensity of snow is characterized as:
1) light when the visibility is 1 km or more;
2) moderate when the visibility is less than 1 km but not more than 1/2 km;
3) heavy when the visibility is less than 1/2 km.
it is found in the atmosphere as snow crystals, hail, ice pellets, etc., and on the earth’s surface in forms such as hoarfrost, rime, glaze, sea ice, glacier ice, ground ice, frazil, anchor ice, etc.
This form of water is, strictly speaking, called ice I, the only one of the several known modifications of solid water substance that is stable at commonly occurring temperatures and pressures. (Some of the other forms have very unusual properties, ice VII, for example, being stable only at pressures above 22 400 kg cm−2, but then existing at temperatures up to about 100°C.) Ice has an open structure because the water molecules bond to their neighbors covalently only in four directions;
it therefore floats on higher density water, where broken molecular bonds permit closer packing. All commonly occurring forms of ice are crystalline, although large single crystals are relatively rare except in glaciers.
The ice crystal lattice possesses hexagonal symmetry that manifests itself in the gross forms of such single crystals as are sometimes found in snow.
At an air pressure of one atmosphere, ice melts at 0°C by definition of the Celsius temperature scale. (Strictly at equilibrium among water, ice, and vapor occurs at +0.01°C, the triple point.) On the other hand, ice does not invariably form in liquid water cooled below this temperature; it has a tendency to supercool, more so in the absence of ice nuclei. See Bernal–Fowler rules, ice crystal.
Wind Chill
| Μετεωρολογικός σταθμός Πειραια. Υψόμετρο: 68μ Weather station in Piraeus – Greece. Elevation: 68m Location: Europe>Greece>Attika>Athens>Piraeus Port |
Wind chill takes into account how the speed of the wind affects our perception of air temperature. Your body warms the surrounding air molecules by transferring heat from your skin. If there’s no air movement, this insulating layer of warm air molecules stays next to your body and off Continue reading
Dew Point
| Μετεωρολογικός σταθμός Πειραια. Υψόμετρο: 68μ Weather station in Piraeus – Greece. Elevation: 68m Location: Europe>Greece>Attika>Athens>Piraeus Port |
The dew point (or dewpoint) is the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. The condensed water is called dew. The dew point is a saturation point.
When the dew point temperature falls below Continue reading
Air Density
| Μετεωρολογικός σταθμός Πειραια. Υψόμετρο: 68μ Weather station in Piraeus – Greece. Elevation: 68m Location: Europe>Greece>Attika>Athens>Piraeus Port |
Air Density (the weight of 1 cubic meter of air ) is a valuable tool for racing enthusiasts, because it helps determine the optimal jetting under current weather conditions.
Note: Air density calculations for Monitor and Perception stations uses the uncorrected bar value. Air density calculations for Vantage Pro station use the corrected/final bar value. Continue reading
