Peppo Weather Station - Glossary

Temperature Terms

Current Temperature (°C - degree Celsius)

This value indicates the current outdoor actual temperature, this value (along with other indexes) is used to calculate the temperature actually felt by humans.

Felt or Apparent Temperature (°C - degree Celsius)

It is the general term for the perceived outdoor temperature, caused by the combined effects of air temperature, relative humidity and wind speed. Click here for additional information on how this value is calculated.

Temperature Trend (°C/h - degree Celsius per hour)

This value indicates how fast the temperature is increasing or decreasing (depending on the value sign) in °C per hour.

Rainfall Terms

Current Rainfall Rate (mm/h - millimeters of rain per hour)

It indicates how fast rain is falling in millimeters per hour (mm/h), the rain fall rate is classified according to the rate of recording/detecting precipitation.

• Very light rain precipitation rate is < 0.25 mm/hour
• Light rain precipitation rate is between 0.25mm/hour and 1.0mm/hour
• Moderate rain precipitation rate is between 1.0 mm/hour and 4.0 mm/hour
• Heavy rain precipitation rate is between 4.0 mm/hour and 16.0 mm/hour
• Very heavy rain precipitation rate is between 16.0 mm/hour and 50 mm/hour
• Extreme rain precipitation rate is > 50.0 mm/hour

Last Hour Rainfall (mm - millimeters of rain)

This value indicates the total millimeters of rain that have fallen over the last 60 minutes, this value will be zero if it had not rain over the last 60 minutes.

Rainfall Today (mm - millimeters of rain)

This value indicates the total cumulative millimeters of rain that have fallen today (as calendar day), every day at midnight this value is reset to zero.

Rainfall Yesterday (mm - millimeters of rain)

This value indicates the total cumulative millimeters of rain that have fallen yesterday (as calendar day).

Rainfall this Month (mm - millimeters of rain)

This value indicates the total cumulative millimeters of rain that have fallen this month (as calendar month), every last day of the month at midnight this value is reset to zero.

Rainfall this Year (mm - millimeters of rain)

This value indicates the total cumulative millimeters of rain that have fallen this month (as calendar year), every 31st of December at midnight this value is reset to zero.

Pressure Terms

Current Pressure (hPa or mbar)

This value indicates the current atmospheric pressure in hPa, for more info on how pressure influences the weather click here.

Current Pressure Trend (hPa/h - hPa or mbar per hour)

This value indicates how fast the pressure is increasing or decreasing (depending on the value sign) in hPa per hour, for more info on how pressure changes influences the weather click here.

Wind Terms

Latest Wind Speed (Km/h - Kilometers per hour)

This value indicates the latest recorded wind speed in Kilometers per hour.

Average Wind Speed (Km/h - Kilometers per hour)

This value indicates the average wind speed recorded over the last hour in Kilometers per hour.

Wind Direction (° - degrees)

This value indicates the direction of the wind in degrees, North is 0°, East is 90°, south is 180° and west is 270°, a value of 90E means that the wind is coming from East blowing toward the west.

10 minutes Wind Gust (Km/h - Kilometers per hour)

This value indicates the highest wind gust, in Kilometers per hour, recorded over the last 10 minutes.

Wind Gust High (Km/h - Kilometers per hour)

This value indicates the highest wind gust, in Kilometers per hour, recorded since midnight.

Solar Indexes

UV Index

The ultraviolet index or UV Index is an international standard measurement of the strength of ultraviolet (UV) radiation from the sun at a particular place and time.

Solar Radiation

Solar irradiance is a measure of the irradiance (power per unit area on the Earth's surface) produced by the Sun in the form of electromagnetic radiation, which is perceived by humans as sunlight.

Solar Radiation Theoretical Max

This value indicates the maximum solar radiation value at any given time that can be theoretically recorded at the sensor location, see more info here.

Solar Radiation / Solar Radiation Theoretical Max (% - Percentage)

This value represent the Solar Radiation / Solar Radiation Theoretical Max expressed in percentage. In case the sky is completely clean and the atmosphere is perfectly clean this value should be 100% or close. In case the sky is completely covered by thick clouds this value should be close to 0%.

Radiation filtering (% - Percentage)

This value represent the inverse of Solar Radiation / Solar Radiation Theoretical Max expressed in percentage. In case the sky is completely clean and the atmosphere is perfectly clean this value should be 0% or close. In case the sky is completely covered by thick clouds this value should be close to 100%.

Cloud Base (mt - meters)

The cloud base (or the base of the cloud) is the lowest altitude of the visible portion of the cloud. It is traditionally expressed either in m or feet above mean sea level (or planetary surface), or as the corresponding pressure level in hectopascal (hPa, equivalent to millibar).

Sun Properties

Apparent Sunrise (HH:MM - Time)

Due to atmospheric refraction, sunrise occurs shortly before the sun crosses above the horizon. Light from the sun is bent, or refracted, as it enters earth's atmosphere. This effect causes the apparent sunrise to be earlier than the actual sunrise. Similarly, apparent sunset occurs slightly later than actual sunset. The sunrise and sunset times reported in our calculator have been corrected for the approximate effects of atmospheric refraction. However, it should be noted that due to changes in air pressure, relative humidity, and other quantities, we cannot predict the exact effects of atmospheric refraction on sunrise and sunset time. Also note that this possible error increases with higher (closer to the poles) latitudes. See Apparent Sunrise Figure.

Solar Noon (HH:MM - Time)

Defined for a given day for a specific longitude, it is the time when the sun crosses the meridian of the observer's location. At solar noon, a shadow cast by a vertical pole will point either directly north or directly south, depending on the observer's latitude and the time of year.

Apparent Sunset (HH:MM - Time)

Due to atmospheric refraction, sunrise occurs shortly before the sun crosses above the horizon. Light from the sun is bent, or refracted, as it enters earth's atmosphere. This effect causes the apparent sunrise to be earlier than the actual sunrise. Similarly, apparent sunset occurs slightly later than actual sunset. The sunrise and sunset times reported in our calculator have been corrected for the approximate effects of atmospheric refraction. However, it should be noted that due to changes in air pressure, relative humidity, and other quantities, we cannot predict the exact effects of atmospheric refraction on sunrise and sunset time. Also note that this possible error increases with higher (closer to the poles) latitudes. See Apparent Sunrise Figure.

Sun Azimuth & Elevation (° - degrees)

It is an angular coordinate system for locating positions in the sky. Azimuth is measured clockwise from true north to the point on the horizon directly below the object. Elevation is measured vertically from that point on the horizon up to the object. If you know the azimuth of a constellation is 135° from north, and the elevation is 30°, you can look toward the southeast, about a third of the way up from the horizon to locate that constellation. Because our planet rotates, azimuth and elevation numbers for stars and planets are constantly changing with time and with the observer's location on earth. See Azimuth/Elevation/Zenith Figure.

Equation of Time (min - minutes)

It is an astronomical term accounting for changes in the time of solar noon for a given location over the course of a year. Earth's elliptical orbit and Kepler's law of equal areas in equal times are the culprits behind this phenomenon. Click here to see a plot of the equation of time vs. day of the year

Solar Declination (° - degrees)

It is the declination of the sun. The solar declination varies from -23.44° at the (northern hemisphere) winter solstice, through 0° at the vernal equinox, to +23.44° at the summer solstice. The variation in solar declination is the astronomical description of the sun going south (in the northern hemisphere) for the winter. Click on Solar Declination Graph to see how the solar declination varies over the year. Click on Solar Paths Figure to see the seasonal solar paths projected on the celestial sphere. For a ground-based view of the seasonal solar paths for different latitudes, see: 0° (the Equator), 23°N (the Tropic of Cancer), 40°N (Boulder, CO), 71°N (the Arctic Circle), and 90° (the North Pole).

Other Indexes

Dew Point (°C - degree Celsius)

The dew point is the temperature at which the water vapor in air at constant barometric pressure condenses into liquid water at the same rate at which it evaporates. At temperatures below the dew point, water will leave the air. The condensed water is called dew when it forms on a solid surface.

Wind Chill (°C - degree Celsius)

Wind-chill or windchill, (popularly wind chill factor) is the perceived decrease in air temperature felt by the body on exposed skin due to the flow of air. Wind chill numbers are always lower than the air temperature for values where the formula is valid. When the apparent temperature is higher than the air temperature, the heat index is used instead.

Heat Index (°C - degree Celsius)

The heat index (HI) or humiture or humidex (not to be confused with the Canadian humidex) is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature—how hot it feels. The result is also known as the "felt air temperature" or "apparent temperature". For example, when the temperature is 32 °C (90 °F) with very high humidity, the heat index can be about 41 °C (106 °F).

Humidity Index (°C - degree Celsius)

The humidex (short for "humidity index") is an index number used by Canadian meteorologists to describe how hot the weather feels to the average person, by combining the effect of heat and humidity. The humidex is a unit-less number based on the dew point, but it is equivalent to dry temperature in degrees Celsius. For example, if the temperature is 30 °C (86 °F), and the calculated humidex is 40, then it indicates the humid heat feels approximately like a dry temperature of 40 °C (104 °F).

Outdoor Humidity (% - Percentage)

Relative humidity (abbreviated RH) is the ratio of the partial pressure of water vapor to the saturation vapor pressure of water at the same temperature. Relative humidity depends on temperature and the pressure of the system of interest.