Climate change is a prevalent issue all around the world. Changes in the temperature and precipitation, as well as their distributions, are the evidence of climate change. Therefore, the objective of this study was to gather and standardize information about temperature (maximum and minimum temperatures and the discrepancy between them) and precipitation in Iran’s environmental zones. The long-term meteorological dataset was gathered from 47 synoptic stations for 66 years (1951–2017). Linear regression was employed to show the type and trend of changes in the studied variables. The Köppen method and UNESCO aridity index were adopted for climate classification based on temperature and precipitation criteria, respectively. Based on the Köppen method, the climate of Iran is defined into 4 environmental zones consisting of the arid desert (Bw), semi-arid (Bs), humid with mild winters (C), and humid with severe winters (D). On the basis of the UNESCO aridity index, the climate of Iran is classified into 5 environmental zones including very dry, dry, semi-dry, humid, and very humid. Results demonstrated that at 42 stations (89% of stations), the slope of the trend line was positive and long-term annual average temperatures of 5 stations (11% of stations) were negative. Furthermore, for precipitation, 11 stations (25% of stations) had positive trend and 33 stations had a negative trend (75% of stations). Finally, it was found that there are significant changes in both temperature and precipitation. On the other hand, an overall increasing trend in temperature and a decreasing trend in precipitation were observed from high-altitude or high-latitude cold areas to low-latitude regions such as costal lines in Iran.

气候变化是世界各地普遍存在的问题。温度和降水的变化及其分布是气候变化的证据。因此，本研究的目的是收集和标准化有关伊朗环境区的温度（最高和最低温度及其之间的差异）和降水的信息。长期的气象数据集来自66个天气观测站，历时66年（1951-2017）。线性回归用来显示研究变量变化的类型和趋势。根据温度和降水标准分别采用了柯本方法和教科文组织干旱指数进行气候分类。根据柯本方法，伊朗的气候被定义为4个环境区，包括干旱沙漠（Bw），半干旱（Bs），冬季温和潮湿（C），冬季严酷潮湿（D）。根据教科文组织的干旱指数，伊朗的气候分为5个环境区，包括非常干燥，干燥，半干燥，潮湿和非常潮湿。结果表明，在42个站（占站的89％）处，趋势线的斜率是正的，而5个站（占站的11％）的长期年平均温度是负的。此外，降水量有11个站（占站的25％）呈正趋势，有33个站有负趋势（占站的75％）。最后，发现温度和降水量都有明显变化。另一方面，