The Mesonet long-term averages utilize daily data (e.g. daily average, daily maximum/minimum, or daily total) for every current and past Oklahoma Mesonet station. For a station's data to be used in one of the maps or graphs, at least 90% of the data must be valid during the respective period. Data from relocated Mesonet stations (e.g. "Norman - retired 2002" and "Norman") are not combined into a single station record.

Each season consists of a three month period of data. Spring contains the months of March, April, and May; Summer has June, July, and August; Fall has September, October, and November; and Winter has December, January, and February. For Winter, the year corresponds to the end of the season (e.g. Winter 2010 has December 2009, January 2010, and February 2010).

The smoothing option on the graphs applies a five day smoothing to the data. Thus, each day also has the previous five and the following five days data averaged into its calculation.

**Air Temperature**

Variable Name | Description |

Average Maximum Air Temperature | Average of daily maximum air temperature. |

Average Minimum Air Temperature | Average of daily minimum air temperature. |

Average Air Temperature | Average of all 5-minute air temperature observations. |

Average 30-foot Air Temperature | Average of all 5-minute 30-foot air temperature observations. |

Average Minimum Wind Chill Temperature | Average of daily minimum wind chill temperature. |

Average Maximum Heat Index Temperature | Average of daily maximum heat index temperature. |

Average Heating Degree Days | Average number of heating degree days. |

Average Cooling Degree Days | Average number of cooling degree days. |

**Humidity**

Variable Name | Description |

Average Maximum Relative Humidity | Average of daily maximum 5-minute averaged relative humidity. |

Average Minimum Relative Humidity | Average of daily minimum 5-minute averaged relative humidity. |

Average Relative Humidity | Average of 5-minute averaged relative humidity. |

Average Maximum Dew Point Temperature | Average of daily maximum dew point temperature. |

Average Minimum Dew Point Temperature | Average of daily minimum dew point temperature. |

Average Dew Point Temperature | Average of daily average dew point temperature. |

**Wind Speed**

Variable Name | Description |

Average Maximum Wind Speed | Average of daily maximum 5-minute averaged wind speed at 33 feet above the ground. |

Average Minimum Wind Speed | Average of daily minimum 5-minute averaged wind speed at 33 feet above the ground. |

Average Wind Speed | Average of daily average 5-minute averaged wind speed at 33 feet above the ground. |

Average Maximum Wind Speed Gust | Average of daily maximum 5-minute wind speed gust at 33 feet above the ground. |

Average Maximum 6.5-foot Wind Speed | Average of daily maximum 5-minute averaged wind speed at 6.5 feet above the ground. |

Average Minimum 6.5-foot Wind Speed | Average of daily minimum 5-minute averaged wind speed at 6.5 feet above the ground. |

Average 6.5-foot Wind Speed | Average of daily average 5-minute averaged wind speed at 6.5 feet above the ground. |

**Pressure**

Variable Name | Description |

Average Maximum Station Pressure | Average of daily maximum station pressure. |

Average Minimum Station Pressure | Average of daily minimum station pressure. |

Average Station Pressure | Average of daily average station pressure. |

Average Maximum Mean Sea Level Pressure | Average of daily maximum station pressure reduced to sea level. |

Average Minimum Mean Sea Level Pressure | Average of daily minimum station pressure reduced to sea level. |

Average Mean Sea Level Pressure | Average of daily average station pressure reduced to sea level. |

**Soil Temperature**

Variable Name | Description |

Avg. Maximum 2-inch Soil Temperature Below Sod | Average of daily maximum soil temperature under native vegetation at a depth of 2 inches. |

Avg. Minimum 2-inch Soil Temperature Below Sod | Average of daily minimum soil temperature under native vegetation at a depth of 2 inches. |

Average 2-inch Soil Temperature Below Sod | Average of daily average soil temperature under native vegetation at a depth of 2 inches. |

Avg. Maximum 4-inch Soil Temperature Below Sod | Average of daily maximum soil temperature under native vegetation at a depth of 4 inches. |

Avg. Minimum 4-inch Soil Temperature Below Sod | Average of daily minimum soil temperature under native vegetation at a depth of 4 inches. |

Average 4-inch Soil Temperature Below Sod | Average of daily average soil temperature under native vegetation at a depth of 4 inches. |

Avg. Max. 4-inch Soil Temperature Below Bare Soil | Average of daily maximum soil temperature under bare soil at a depth of 4 inches. |

Avg. Min. 4-inch Soil Temperature Below Bare Soil | Average of daily minimum soil temperature under bare soil at a depth of 4 inches. |

Average 4-inch Soil Temperature Below Bare Soil | Average of daily average soil temperature under bare soil at a depth of 4 inches. |

**Soil Moisture**

Variable Name | Description |

Average 2-inch Fractional Water Index | Average of daily fractional water index (1=wet, 0=dry) at a depth of 2 inches. (Ref 1; Eq 4) |

Average 10-inch Fractional Water Index | Average of daily fractional water index (1=wet, 0=dry) at a depth of 10 inches. (Ref 1; Eq 4) |

Average 24-inch Fractional Water Index | Average of daily fractional water index (1=wet, 0=dry) at a depth of 24 inches. (Ref 1; Eq 4) |

4-inch Plant Available Water | The amount of water available to plants in the top 4 inches of the soil. |

16-inch Plant Available Water | The amount of water available to plants in the top 16 inches of the soil. |

32-inch Plant Available Water | The amount of water available to plants in the top 32 inches of the soil. |

**Rainfall, Evaporation, Evapotranspiration, and Radiation**

Variable Name | Description |

Total Rainfall | Total rainfall accumulation. |

Total Rainfall with Estimates | Total rainfall accumulation with estimates used in place of missing values. |

Total Evaporation | Total evaporation. |

Total Potential Evapotranspiration, Tall Crop | Total potential evapotranspiration (Ref 2; Eq. 1) utilizing surface characteristics related to tall crops (Ref 2; Table. 1) |

Total Potential Evapotranspiration, Short Crop | Total potential evapotranspiration (Ref 2; Eq. 1) utilizing surface characteristics related to short crops (Ref 2; Table. 1) |

Average Maximum Solar Radiation | Average of maximum daily solar radiation. |

Daily Average of Total Solar Radiation | Daily average of total daily solar radiation. |

Daily Average of Estimated Net Radiation | Daily average of estimated net radiation. (Ref 2; Eq 15) |

Percent Sunshine | Average of estimated sunshine received (1=sun; 0 = no sun/night). (Ref 2; Eq. 18) |

**References:**

- Illston, B.G., J.B. Basara, D.K. Fischer, R.L. Elliott, C. Fiebrich, K.C. Crawford, K. Humes, and E. Hunt, 2008: Mesoscale Monitoring of Soil Moisture Across a Statewide Network. J. of Atmos. and Oceanic Tech, 25, 167-182. (download PDF)
- American Society of Civil Engineers, 2005: "The ASCE Standardized Reference Evapotranspiration Equation". (download PDF)