Monthly Means Of Daily Average Temperature (C) October

Under conditions of natural vegetation, mean temperatures are used to distinguish between three broad thermal divisions of plants, viz. mega-thermal plants, which require mean monthly temperatures above 20 degree Celsius for at least 4 months of the year; micro-thermal plants, which grow where 8 months or longer have means below 10 degree Celsius; and the meso-thermal plants of the mid-latitudes, which cover most of South Africa, and whose physiology is adapted to the strong seasonal rhythms which are experienced over most of the southern African subcontinent. Month-by-month variations of mean temperature influence the geographic range and the optimum growth areas of certain vegetation and crop species, especially those with life-cycles extending one year or less.

Assuming a daily average temperature to be represented by the mean of that days minimum and maximum temperatures, these averages were derived from the 50 year (1950 – 1999) time series of quality controlled daily minimum and maximum temperatures which were generated from over 970 qualifying temperature stations using infilling and record extension techniques developed by Schulze and Maharaj (2004). From these point location time series, 50 years of daily mean temperature values were derived at each of 429 700 one arc minute (1.7 km x 1.7 km) grid points covering South Africa, using regionally and seasonally determined lapse rates and other physically appropriate spatial interpolation approaches (Schulze and Maharaj, 2004). From the daily values, monthly means and standard deviations of daily values for each month of the year could be computed for purposes of mapping and production of tables of statistics for each of the nine provinces of the RSA as well as for Swaziland and Lesotho.

在自然植被条件下，平均温度被用于区分植物的三大热型类别，即：巨热植物（mega-thermal plants）——其生长需要每年至少4个月的月平均温度高于20摄氏度；微热植物（micro-thermal plants）——生长于每年8个月或更长时间月平均温度低于10摄氏度的区域；以及中纬度的中热植物（meso-thermal plants）——这类植物覆盖南非大部分地区，其生理机能已适应非洲南部次大陆大部分区域所经历的强烈季节节律。

月平均温度的逐月变化会影响特定植被和作物物种的地理分布范围及最适生长区域，尤其是生命周期不超过一年的物种。

假设日平均温度由当日最低与最高温度的平均值表示，这些日平均温度数据来源于1950-1999年共50年的质控日最低和最高温度时间序列；该时间序列是通过Schulze与Maharaj（2004）开发的填充与记录扩展技术（infilling and record extension techniques），基于970余个符合条件的气象站数据生成的。

基于这些点位时间序列，研究人员采用区域与季节特异性的气温递减率（lapse rate）及其他物理上合理的空间插值方法（spatial interpolation approaches）（Schulze与Maharaj，2004），在覆盖南非的429700个1角分（约1.7km×1.7km）网格点上，生成了各点50年的日平均温度数据。

从日平均温度数据中，可计算出每年各月的月平均值及日值标准差，用于绘制地图及生成南非共和国（RSA）九个省份、斯威士兰和莱索托的统计表格。