The time-placement scheme of climate extreme changes is important. In this regard, a set of a compound indices derived using daily resolution climatic time series data is examined to assess climate change in Iran. The compound indices were examined for 47 synoptic meteorological stations during 1981–2015. The results show that most stations experienced a negative trend for the cool/dry (CD) and cool/wet (CW) index and a positive trend in CW was observed in some dispersed small areas. Both warm/dry (WD) and warm/wet (WW) indices have similar behavior, but the magnitude and spatial consistency of WW days were much less than WD days. The results show that more than 80% of stations experienced a decrease in the annual occurrence of the cold modes and an increase in the annual occurrence of the warm modes. On the other hand, universal thermal climate index (UTCI) change demonstrated a significant increase in the annual occurrence of strong heat stress (32–38 °C) and significant decrease in the annual occurrence of no thermal stress class (9–26 °C). Moreover, trends in tourism climate index (TCI), including TCI≥ 60 and TCI≥ 80, showed similar changes but with weak spatial coherence.

气候极端变化的时间安排方案很重要。在这方面，对使用每日分辨率气候时间序列数据得出的一组复合指数进行了评估，以评估伊朗的气候变化。在1981-2015年期间检查了47个天气气象站的复合指数。结果表明，大多数站点的冷/干（CD）和冷/湿（CW）指数呈负趋势，在一些分散的小区域中，CW呈正趋势。暖/干（WD）指数和暖/湿（WW）指数都具有相似的行为，但是WW天的大小和空间一致性远小于WD天。结果表明，超过80％的气象站经历了冷模式的年发生次数减少，而暖模式的年发生次数增加了。另一方面，全球热气候指数（UTCI）的变化表明强热应力（32–38 ° C）的年发生率显着增加，而无热应力等级（9–26°C）的年发生率显着下降）。此外，在旅游气候指数趋势（TCI），包括TCI ≥ 60和TCI ≥ 80，显示了相似的变化，但与空间相干性弱。