The annual average temperature in Tongchuan is 8.9 ℃-12.3 ℃, showing a decreasing trend from southeast to northwest. The extreme maximum temperature occurred in the southern Taiyuan District, at 39.7°C (June 11, 1972); the extreme minimum temperature occurred in the northwest mountainous area, at -21°C (January 7, 1956). The temperature in mountainous areas decreases with the increase of terrain: for every 100 meters of terrain increase, the average temperature drops by 0.59℃. The temperature in Tongchuan is characterized by cold winters, hot summers, rapid heating in spring, rapid cooling in autumn, large daily temperature differences, and large day-night temperature differences. The period when the daily average temperature in Tongchuan is greater than or equal to 0°C is the growing season of crops, with an accumulated temperature of 3546.4°C—4613.9°C. The period of 20℃ is the period when crops quickly accumulate dry matter, and the accumulated temperature is 620℃-2474.6℃. In terms of regional distribution, it decreases from southeast to northwest, and there is a huge gap between north and south. The distribution is uneven during the year, and the inter-annual fluctuations are large. The annual difference of accumulated temperature equal to or greater than 0℃ is between 557.2℃-604.4℃. 84% of accumulated temperature greater than or equal to 0°C was concentrated in April to September; 90% of accumulated temperature greater than or equal to 10°C was concentrated in May to September.