LawnByCounty

Counties with the Most Growing Degree Days

Published May 2, 2026

Growing Degree Days (GDD) measure the accumulated heat available for plant growth. The higher the GDD, the more energy your lawn has to grow, recover from damage, and outcompete weeds. Counties with high GDD values support aggressive warm-season grasses and rapid turf establishment.

We identified the 25 counties with the highest Growing Degree Days (base 50°F) — the places where heat accumulation gives lawns a powerful growth advantage.

Counties with the Most Growing Degree Days

Monroe County, FL leads with 10,190.636 GDD (base 50°F) annually. These counties can support Bermuda grass and other heat-loving species that need significant thermal energy.

RankCountyStateGDD (Base 50°F)Growing SeasonHardiness Zone
1Monroe CountyFL10,190.636N/A11b
2Broward CountyFL9,764.6N/A11a
3Miami-Dade CountyFL9,705.354N/A11a
4Starr CountyTX9,370.65N/A9b
5Collier CountyFL9,261.029N/A10b
6Lee CountyFL9,209.85N/A10b
7Cameron CountyTX9,193.8N/A10a
8Palm Beach CountyFL9,176.171N/A10b
9Charlotte CountyFL9,164.1N/A10a
10Hidalgo CountyTX9,138.7N/A10a
11Zapata CountyTX9,010.9N/A9b
12Okeechobee CountyFL9,004.2N/A10a
13Martin CountyFL8,973.95N/A10b
14Hillsborough CountyFL8,946.8N/A9b
15Jim Hogg CountyTX8,852.8N/A9b
16Yuma CountyAZ8,838.443N/A10a
17Hendry CountyFL8,809.85N/A10a
18Willacy CountyTX8,805.9N/A10a
19Indian River CountyFL8,791.7N/A10a
20Polk CountyFL8,773.72N/A10a
21Pinellas CountyFL8,730.6N/A10a
22Imperial CountyCA8,692.38N/A10a
23Sarasota CountyFL8,673.6N/A10a
24Webb CountyTX8,649.55N/A9b
25Kleberg CountyTX8,602.9N/A9b

Methodology

Growing Degree Days (base 50°F) represent accumulated daily heat above 50°F, a standard benchmark for turfgrass and plant growth. Data from NOAA climate normals.

Data sourced from USDA Plant Hardiness Zone Map (2023), NOAA National Centers for Environmental Information (1991-2020 Climate Normals), and US Drought Monitor. All figures represent long-term averages and may differ from individual-year observations.

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