## 4 Discussion  
The present study analyzed the annual and seasonal characteristics of the average nighttime and daytime LST, its trend (in terms of total change), and SUHI effects, for over 20 major urban agglomerations in India and surrounding countries for a period of 23 years (2000 to 2023). The study revealed an evident warming trend in all cities during nighttime, while cooling trends were observed in most cities during daytime (except for Dhaka, Kolkata, Yangon, and Colombo, which observed a total change of 1.50, 0.61, 0.32 and 1.57 \({}^{\circ}\)C, respectively) over the past two decades (Table 1). This is in agreement with previous LST studies, particularly over Pune, Kolkata, Jaipur, Ahmedabad and Bangalore, which revealed a general nighttime warming trend in all of the above cities, but a daytime warming trend in Kolkata and Ahmedabad and a daytime urban \begin{table}
\begin{tabular}{l c c c c c c c c c c c c c c c} \hline
**SL** & **City** & **Ann.** & **AMJ** & **DJF** & **Jan** & **Feb** & **Mar** & **Apr** & **May** & **Jun** & **Jul** & **Aug** & **Sep** & **Oct** & **Nov** & **Dec** \\ \hline
11. & Surat & 0.45 & 0.66 & 0.17 & 0.03 & 0.31 & 0.70 & 1.03 & 0.79 & 0.17 & \(-\)0.07 & \(-\)0.11 & 1.03 & 1.14 & 0.60 & 0.18 \\ \hline
12. & Pune & \(-\)0.13 & \(-\)0.53 & \(-\)0.31 & \(-\)0.31 & \(-\)0.48 & \(-\)0.77 & \(-\)0.84 & \(-\)0.68 & \(-\)0.07 & 0.16 & 0.69 & 0.67 & 0.41 & 0.11 & \(-\)0.15 \\ \hline
13. & Yangon & 0.83 & 0.34 & 0.41 & 0.49 & 0.11 & \(-\)0.54 & \(-\)0.90 & \(-\)0.12 & 2.03 & 1.92 & 1.50 & 2.15 & 1.64 & 0.62 \\ \hline
14. & Lucknow & 0.80 & 0.36 & 0.72 & 0.80 & 1.39 & 1.69 & 0.71 & 0.33 & 0.05 & 0.69 & 1.33 & 1.59 & 0.80 & \(-\)0.06 & \(-\)0.02 \\ \hline
15. & Faisalabad & 0.92 & 1.07 & 0.66 & 0.61 & 1.17 & 1.59 & 1.62 & 0.77 & 0.81 & 0.98 & 0.81 & 1.06 & 0.94 & 0.51 & 0.19 \\ \hline
16. & Jaipur & \(-\)0.92 & \(-\)1.48 & \(-\)0.52 & \(-\)0.43 & \(-\)0.20 & \(-\)0.68 & \(-\)1.69 & \(-\)1.51 & \(-\)1.24 & \(-\)0.75 & 0.05 & \(-\)0.33 & \(-\)1.71 & \(-\)1.57 & \(-\)0.95 \\ \hline
17. & Kanpur & 0.14 & \(-\)0.91 & 0.60 & 0.59 & 1.41 & 1.52 & \(-\)0.32 & \(-\)1.07 & \(-\)1.35 & \(-\)0.35 & 0.65 & 0.75 & 0.06 & \(-\)0.38 & \(-\)0.19 \\ \hline
18. & Dhanbad & 0.32 & 0.10 & 0.33 & 0.30 & 0.24 & 0.10 & 0.15 & 0.18 & \(-\)0.02 & 0.14 & 0.22 & 0.55 & 0.78 & 0.69 & 0.44 \\ \hline
19. & Coimbatore & 0.21 & 0.06 & \(-\)0.08 & \(-\)0.14 & \(-\)0.46 & \(-\)0.47 & \(-\)0.39 & 0.13 & 0.43 & 0.79 & 0.56 & 0.59 & 0.69 & 0.50 & 0.36 \\ \hline
20. & Colombo & 1.36 & 1.25 & 1.27 & 1.33 & 1.17 & 1.00 & 1.16 & 1.26 & 1.31 & 1.62 & 1.67 & 1.54 & 1.64 & 1.31 & 1.32 \\ \hline \end{tabular} (Ann.: Annual; AMJ: April–May-June; DJF: December-January–February).  
\end{table} 
Table 7: _Cont._  
Figure 11: Monthly time series showing (**a,b**) average daytime LST, and (**c,d**) daytime SUHI effect over selected major Indian cities for the period 2000–2023. cooling trend in Pune, Jaipur and Bangalore [88; 94; 95; 96]. Daytime urban cooling has also been reported by scientists specifically for the majority of urban regions in central India and the Indo-Gangetic basin [89]. LST is a product of the interplay between various climatic and environmental factors with the land surface, which is seemingly impacted by both atmospheric and land processes. Daytime and nighttime LST values are influenced by different degrees of these interactions. The daytime LST change was found to be affected by factors that exhibit less variability in space but more variability in time, such as solar radiation, while the nighttime LST change was found to be governed by factors that exhibit more variability in space but less variability in time, such as longwave radiation exchange, land cover change, and soil moisture change [97].