# On the Evolution of U.S. Temperature Dynamics

## TL;DR

This paper investigates how U.S. temperature dynamics, including mean levels and daily volatility, have evolved over the past fifty years, revealing changes in diurnal temperature range seasonality.

## Contribution

It introduces a comparative analysis of temperature level and volatility trends using linear models with time-varying coefficients over half a century.

## Key findings

- Evolving seasonality in diurnal temperature range (DTR)
- Stable seasonality in average temperature (AVG)
- Evidence of changing temperature volatility patterns

## Abstract

Climate change is a massive multidimensional shift. Temperature shifts, in particular, have important implications for urbanization, agriculture, health, productivity, and poverty, among other things. While much research has documented rising mean temperature \emph{levels}, we also examine range-based measures of daily temperature \emph{volatility}. Specifically, using data for select U.S. cities over the past half-century, we compare the evolving time series dynamics of the average temperature level, AVG, and the diurnal temperature range, DTR (the difference between the daily maximum and minimum temperatures). We characterize trend and seasonality in these two series using linear models with time-varying coefficients. These straightforward yet flexible approximations provide evidence of evolving DTR seasonality and stable AVG seasonality.