18 Miss. Code. R. 20-1-1-V.4
According to the State Climatologist Office at Mississippi State University, Mississippi is located in the humid subtropical climate region, characterized by temperate winters; long, hot summers; and rainfall that is fairly evenly distributed through the year. However, the state is subject to periods of both drought and flood, and the climate rarely seems to bring "average" conditions. More typical would be an expectation of "feast or famine" with regard to weather events as the climate delivers energy and moisture in subtropical latitudes between a large landmass to the north and the Gulf of Mexico to the south.
Prevailing southerly winds provide moisture for high humidity and potential discomfort from May through September. Locally violent and destructive thunderstorms are a threat on an average of about 60 days each year. Eight hurricanes have struck Mississippi's coast since 1895, and tornadoes are a particular danger, especially during the spring season.
Normal mean annual temperatures range from 62F in the north to 68F along the coast. Low temperatures have dropped to 16F below zero while high temperatures exceed 90F over 100 days each year. Temperatures routinely exceed 100F at many places in the state each year and drop to zero or lower an average of once in five years in the state. Freezing temperatures reach the Gulf coast almost every winter. Normal precipitation ranges from about 50 to 65 inches across the state from north to south. Measurable snow or sleet falls on some part of the state in 95% of the years.
In essence, Mississippi has a climate characterized by absence of severe cold in winter but by the presence of extreme heat in summer. The ground rarely freezes and outdoor activities are generally planned year-round. Cold spells are usually of short duration and the growing season is long. Rainfall is plentiful, but so are dry spells and sunshine.
The State of Mississippi is divided into three climatic regions. Listed below is a comparison of 2021(January) to 2022 (July) Heating and Cooling Degree Days according to the National Weather Service and the Weather Data Depot (http://www.weatherdatadepot.com/) per region.
Region | 2021 | 2022 | +/- | 2021 | 2022 | +/- |
Heating Degree Days (HDD) | Heating Degree Days (HDD) | Comparison % Increase/Decrease Days | Cooling Degree Days (CDD) | Cooling Degree Days (CDD) | Comparison % Increase/Decrease Days | |
Tupelo (Region # 1) North MS | 1182 | 1164 | -2% | 3305 | 2116 | 18% |
Jackson (Region # 2) Central MS | 1282 | 882 | -10% | 3684 | 2295 | 17% |
Gulfport (Region # 3) South MS | 819 | 624 | -5% | 3935 | 2410 | 14% |
These climatic variances within the State affect how the weatherization program is designed and targets the number of units weatherized. It also affects energy savings realized in different regions, as well as energy usage and cost (labor/material).
18 Miss. Code. R. 20-1-1-V.4