Virginia climate zones and HVAC design temperatures
Virginia spans 3 IECC climate zones. 79% of people live in zone 4A (mixed, humid). In Virginia Beach, heating and cooling equipment is sized for 92°F in summer and 27°F in winter.
Design temperatures for major cities
| City | Zone | Summer 1% | Winter 99% | Water in |
|---|---|---|---|---|
| Virginia Beach | 3A | 92°F | 27°F | 64°F |
| Richmond | 4A | 92°F | 22°F | 62°F |
| Roanoke | 4A | 90°F | 20°F | 61°F |
| Arlington | 4A | 92°F | 23°F | 62°F |
| Charlottesville | 4A | 92°F | 22°F | 62°F |
Summer: exceeded in 1% of hours. Winter: colder in only 1% of hours. Water in: estimated groundwater temperature for tankless water heater sizing. Computed for each county from NOAA hourly weather data, 2015-2024; see where our numbers come from. Hottest summer design in the state: 92°F (Albemarle County); coldest winter design: 9°F (Alleghany County).
Typical equipment sizes in Virginia Beach
One-story house with average insulation (R-13 walls, R-30 attic, double-pane windows), at Virginia Beach's design temperatures. Your house can need more or less; use the calculators for yours.
| House | Central AC | Gas furnace (95% AFUE) | Heat pump |
|---|---|---|---|
| 1,500 sq ft | 2.5 tons | 40,000 BTU | 2.5 tons |
| 2,000 sq ft | 3 tons | 40,000 BTU | 3 tons |
| 2,500 sq ft | 3.5 tons | 40,000 BTU | 3.5 tons + 5 kW backup |
AC size calculator Furnace size calculator Heat pump size calculator
Climate zone by county
From the 2021 International Energy Conservation Code (IECC), as published by the U.S. Department of Energy. The zone sets the insulation and window requirements in the energy code; the number runs from 1 (hottest) to 8 (coldest), and the letter is A for moist, B for dry and C for marine.
Zone 3A: warm, humid (19 counties, 20% of people)
| County | Summer 1% | Winter 99% |
|---|---|---|
| Brunswick County | 91°F | 23°F |
| Chesapeake city | 91°F | 24°F |
| Emporia city | 91°F | 22°F |
| Franklin city | 91°F | 22°F |
| Franklin County | 90°F | 20°F |
| Greensville County | 91°F | 22°F |
| Halifax County | 91°F | 22°F |
| Hampton city | 91°F | 25°F |
| Isle of Wight County | 91°F | 25°F |
| Mecklenburg County | 90°F | 22°F |
| Newport News city | 91°F | 24°F |
| Norfolk city | 91°F | 28°F |
| Pittsylvania County | 91°F | 22°F |
| Portsmouth city | 91°F | 28°F |
| Southampton County | 91°F | 22°F |
| Suffolk city | 91°F | 24°F |
| Surry County | 92°F | 22°F |
| Sussex County | 92°F | 22°F |
| Virginia Beach city | 92°F | 27°F |
Zone 4A: mixed, humid (110 counties, 79% of people)
| County | Summer 1% | Winter 99% |
|---|---|---|
| Accomack County | 89°F | 22°F |
| Albemarle County | 92°F | 22°F |
| Alexandria city | 92°F | 23°F |
| Amelia County | 91°F | 21°F |
| Amherst County | 90°F | 20°F |
| Appomattox County | 90°F | 20°F |
| Arlington County | 92°F | 23°F |
| Augusta County | 89°F | 15°F |
| Bedford County | 90°F | 20°F |
| Bland County | 81°F | 13°F |
| Botetourt County | 90°F | 20°F |
| Bristol city | 87°F | 19°F |
| Buchanan County | 82°F | 16°F |
| Buckingham County | 91°F | 20°F |
| Buena Vista city | 90°F | 20°F |
| Campbell County | 90°F | 20°F |
| Caroline County | 92°F | 21°F |
| Carroll County | 82°F | 16°F |
| Charles City County | 92°F | 22°F |
| Charlotte County | 91°F | 20°F |
| Charlottesville city | 92°F | 22°F |
| Chesterfield County | 92°F | 22°F |
| Clarke County | 88°F | 18°F |
| Colonial Heights city | 91°F | 21°F |
| Craig County | 90°F | 20°F |
| Culpeper County | 92°F | 18°F |
| Cumberland County | 91°F | 20°F |
| Danville city | 91°F | 22°F |
| Dickenson County | 82°F | 16°F |
| Dinwiddie County | 91°F | 21°F |
| Essex County | 91°F | 21°F |
| Fairfax city | 91°F | 18°F |
| Fairfax County | 92°F | 19°F |
| Falls Church city | 92°F | 23°F |
| Fauquier County | 92°F | 18°F |
| Floyd County | 86°F | 17°F |
| Fluvanna County | 92°F | 22°F |
| Frederick County | 88°F | 18°F |
| Fredericksburg city | 92°F | 21°F |
| Galax city | 82°F | 16°F |
| Giles County | 87°F | 17°F |
| Gloucester County | 91°F | 22°F |
| Goochland County | 92°F | 21°F |
| Grayson County | 82°F | 16°F |
| Greene County | 92°F | 22°F |
| Hanover County | 92°F | 21°F |
| Harrisonburg city | 89°F | 15°F |
| Henrico County | 92°F | 21°F |
| Henry County | 90°F | 19°F |
| Hopewell city | 91°F | 21°F |
| James City County | 91°F | 25°F |
| King and Queen County | 91°F | 21°F |
| King George County | 92°F | 21°F |
| King William County | 91°F | 21°F |
| Lancaster County | 91°F | 22°F |
| Lee County | 88°F | 19°F |
| Lexington city | 79°F | 9°F |
| Loudoun County | 91°F | 19°F |
| Louisa County | 91°F | 18°F |
| Lunenburg County | 91°F | 21°F |
| Lynchburg city | 90°F | 20°F |
| Madison County | 90°F | 19°F |
| Manassas city | 91°F | 19°F |
| Manassas Park city | 91°F | 19°F |
| Martinsville city | 90°F | 19°F |
| Mathews County | 91°F | 24°F |
| Middlesex County | 91°F | 22°F |
| Montgomery County | 86°F | 17°F |
| Nelson County | 89°F | 15°F |
| New Kent County | 91°F | 22°F |
| Northampton County | 91°F | 25°F |
| Northumberland County | 91°F | 23°F |
| Norton city | 82°F | 16°F |
| Nottoway County | 91°F | 21°F |
| Orange County | 90°F | 19°F |
| Page County | 90°F | 18°F |
| Patrick County | 90°F | 19°F |
| Petersburg city | 91°F | 21°F |
| Poquoson city | 91°F | 25°F |
| Powhatan County | 92°F | 21°F |
| Prince Edward County | 91°F | 20°F |
| Prince George County | 91°F | 21°F |
| Prince William County | 91°F | 19°F |
| Pulaski County | 87°F | 17°F |
| Radford city | 87°F | 17°F |
| Rappahannock County | 92°F | 18°F |
| Richmond city | 92°F | 22°F |
| Richmond County | 91°F | 21°F |
| Roanoke city | 90°F | 20°F |
| Roanoke County | 90°F | 20°F |
| Rockbridge County | 79°F | 9°F |
| Rockingham County | 89°F | 15°F |
| Russell County | 87°F | 19°F |
| Salem city | 90°F | 20°F |
| Scott County | 89°F | 19°F |
| Shenandoah County | 90°F | 18°F |
| Smyth County | 84°F | 14°F |
| Spotsylvania County | 92°F | 21°F |
| Stafford County | 92°F | 19°F |
| Staunton city | 89°F | 15°F |
| Tazewell County | 84°F | 14°F |
| Warren County | 88°F | 18°F |
| Washington County | 87°F | 19°F |
| Waynesboro city | 89°F | 15°F |
| Westmoreland County | 91°F | 21°F |
| Williamsburg city | 91°F | 25°F |
| Winchester city | 88°F | 18°F |
| Wise County | 82°F | 16°F |
| Wythe County | 84°F | 14°F |
| York County | 91°F | 24°F |
Zone 5A: cool, humid (4 counties, 0% of people)
| County | Summer 1% | Winter 99% |
|---|---|---|
| Alleghany County | 79°F | 9°F |
| Bath County | 79°F | 9°F |
| Covington city | 79°F | 9°F |
| Highland County | 79°F | 9°F |
Climate data as of 2026-10. Design temperatures may differ by a few degrees from the ACCA Manual J tables your contractor uses; winter values run a little warmer because recent winters have been milder.