ASHRAE Climatic Design Conditions (50 US States & Canada)
Official ASHRAE 99% / 99.6% winter heating dry-bulb and 0.4% / 1.0% summer cooling design conditions across all 50 US states, the District of Columbia, and Canadian metropolitan weather stations. Governed by ASHRAE Handbook of Fundamentals (Chapter 14) and ACCA Manual J (8th Ed).
Showing 87 meteorological stations
| Station / Location | IECC Zone | Winter 99% DB | Winter 99.6% DB | Summer 0.4% DB | Coincident WB | Elevation | Direct Load Sizing Actions |
|---|---|---|---|---|---|---|---|
| Birmingham, ALAlabama | 3A | 22°F | 18°F | 93°F | 76°F | 644 ft | |
| Mobile, ALAlabama | 2A | 29°F | 25°F | 93°F | 78°F | 219 ft | |
| Huntsville, ALAlabama | 3A | 18°F | 14°F | 93°F | 76°F | 629 ft | |
| Anchorage, AKAlaska | 7 | -10°F | -16°F | 71°F | 58°F | 144 ft | |
| Fairbanks, AKAlaska | 8 | -42°F | -48°F | 82°F | 62°F | 434 ft | |
| Phoenix, AZArizona | 2B | 41°F | 38°F | 109°F | 71°F | 1,107 ft | |
| Tucson, AZArizona | 2B | 34°F | 31°F | 103°F | 68°F | 2,584 ft | |
| Flagstaff, AZArizona | 5B | 2°F | -4°F | 86°F | 57°F | 7,014 ft | |
| Little Rock, ARArkansas | 3A | 21°F | 16°F | 96°F | 77°F | 260 ft | |
| Los Angeles (LAX), CACalifornia | 3B | 46°F | 43°F | 80°F | 66°F | 125 ft | |
| San Francisco, CACalifornia | 3C | 41°F | 38°F | 77°F | 61°F | 52 ft | |
| San Diego, CACalifornia | 3B | 46°F | 43°F | 81°F | 68°F | 29 ft | |
| Sacramento, CACalifornia | 3B | 33°F | 30°F | 98°F | 69°F | 26 ft | |
| Fresno, CACalifornia | 3B | 32°F | 29°F | 101°F | 70°F | 336 ft | |
| Denver, COColorado | 5B | 2°F | -4°F | 93°F | 61°F | 5,431 ft | |
| Colorado Springs, COColorado | 5B | 1°F | -5°F | 89°F | 59°F | 6,172 ft | |
| Hartford, CTConnecticut | 5A | 5°F | 0°F | 90°F | 73°F | 180 ft | |
| Wilmington, DEDelaware | 4A | 14°F | 9°F | 91°F | 75°F | 80 ft | |
| Washington (Reagan), DCDistrict of Columbia | 4A | 18°F | 14°F | 93°F | 76°F | 66 ft | |
| Miami, FLFlorida | 1A | 48°F | 44°F | 91°F | 78°F | 13 ft | |
| Orlando, FLFlorida | 2A | 38°F | 33°F | 94°F | 77°F | 96 ft | |
| Tampa, FLFlorida | 2A | 41°F | 36°F | 92°F | 78°F | 19 ft | |
| Jacksonville, FLFlorida | 2A | 31°F | 27°F | 94°F | 77°F | 30 ft | |
| Atlanta, GAGeorgia | 3A | 22°F | 17°F | 91°F | 74°F | 1,010 ft | |
| Savannah, GAGeorgia | 2A | 29°F | 25°F | 94°F | 78°F | 50 ft | |
| Honolulu, HIHawaii | 1A | 64°F | 62°F | 89°F | 73°F | 15 ft | |
| Boise, IDIdaho | 5B | 11°F | 4°F | 96°F | 63°F | 2,858 ft | |
| Chicago (O'Hare), ILIllinois | 5A | -2°F | -7°F | 90°F | 74°F | 672 ft | |
| Springfield, ILIllinois | 4A | 2°F | -4°F | 91°F | 75°F | 597 ft | |
| Indianapolis, INIndiana | 5A | 4°F | -2°F | 89°F | 74°F | 792 ft | |
| Des Moines, IAIowa | 5A | -4°F | -10°F | 91°F | 75°F | 964 ft | |
| Wichita, KSKansas | 4A | 9°F | 3°F | 99°F | 74°F | 1,332 ft | |
| Louisville, KYKentucky | 4A | 13°F | 7°F | 91°F | 75°F | 497 ft | |
| New Orleans, LALouisiana | 2A | 35°F | 30°F | 93°F | 79°F | 4 ft | |
| Portland, MEMaine | 6A | 0°F | -6°F | 85°F | 70°F | 62 ft | |
| Baltimore, MDMaryland | 4A | 15°F | 10°F | 92°F | 75°F | 148 ft | |
| Boston (Logan), MAMassachusetts | 5A | 9°F | 4°F | 89°F | 73°F | 20 ft | |
| Detroit, MIMichigan | 5A | 6°F | 0°F | 89°F | 73°F | 645 ft | |
| Grand Rapids, MIMichigan | 5A | 4°F | -2°F | 88°F | 73°F | 794 ft | |
| Minneapolis / St. Paul, MNMinnesota | 6A | -11°F | -17°F | 89°F | 73°F | 841 ft | |
| Jackson, MSMississippi | 3A | 25°F | 20°F | 95°F | 77°F | 330 ft | |
| St. Louis, MOMissouri | 4A | 9°F | 2°F | 93°F | 76°F | 580 ft | |
| Kansas City, MOMissouri | 4A | 6°F | -1°F | 93°F | 75°F | 791 ft | |
| Billings, MTMontana | 6B | -12°F | -19°F | 92°F | 62°F | 3,567 ft | |
| Omaha, NENebraska | 5A | -2°F | -8°F | 92°F | 75°F | 983 ft | |
| Las Vegas, NVNevada | 3B | 34°F | 30°F | 108°F | 67°F | 2,180 ft | |
| Reno, NVNevada | 5B | 13°F | 7°F | 95°F | 59°F | 4,404 ft | |
| Concord, NHNew Hampshire | 6A | -5°F | -11°F | 88°F | 71°F | 342 ft | |
| Newark, NJNew Jersey | 4A | 14°F | 9°F | 92°F | 75°F | 30 ft | |
| Albuquerque, NMNew Mexico | 4B | 19°F | 14°F | 94°F | 61°F | 5,315 ft | |
| New York (JFK / Central Park), NYNew York | 4A | 15°F | 10°F | 89°F | 74°F | 32 ft | |
| Buffalo, NYNew York | 5A | 5°F | 0°F | 85°F | 71°F | 715 ft | |
| Albany, NYNew York | 5A | 1°F | -5°F | 88°F | 72°F | 290 ft | |
| Charlotte, NCNorth Carolina | 3A | 22°F | 17°F | 92°F | 74°F | 748 ft | |
| Raleigh / Durham, NCNorth Carolina | 3A | 20°F | 15°F | 92°F | 75°F | 435 ft | |
| Fargo, NDNorth Dakota | 7 | -19°F | -25°F | 89°F | 71°F | 900 ft | |
| Columbus, OHOhio | 5A | 6°F | 0°F | 89°F | 73°F | 812 ft | |
| Cleveland, OHOhio | 5A | 7°F | 2°F | 87°F | 72°F | 791 ft | |
| Cincinnati, OHOhio | 4A | 9°F | 3°F | 89°F | 74°F | 883 ft | |
| Oklahoma City, OKOklahoma | 3A | 14°F | 8°F | 99°F | 74°F | 1,290 ft | |
| Portland, OROregon | 4C | 27°F | 22°F | 88°F | 67°F | 30 ft | |
| Philadelphia, PAPennsylvania | 4A | 15°F | 11°F | 91°F | 75°F | 30 ft | |
| Pittsburgh, PAPennsylvania | 5A | 7°F | 2°F | 87°F | 72°F | 1,150 ft | |
| Providence, RIRhode Island | 5A | 10°F | 5°F | 88°F | 73°F | 55 ft | |
| Charleston, SCSouth Carolina | 2A | 29°F | 25°F | 93°F | 78°F | 46 ft | |
| Sioux Falls, SDSouth Dakota | 6A | -10°F | -16°F | 90°F | 73°F | 1,428 ft | |
| Nashville, TNTennessee | 4A | 17°F | 11°F | 92°F | 75°F | 590 ft | |
| Memphis, TNTennessee | 3A | 20°F | 15°F | 95°F | 77°F | 332 ft | |
| Houston (Bush), TXTexas | 2A | 33°F | 28°F | 96°F | 78°F | 96 ft | |
| Dallas / Fort Worth, TXTexas | 3A | 24°F | 19°F | 100°F | 75°F | 607 ft | |
| San Antonio, TXTexas | 2A | 32°F | 27°F | 99°F | 76°F | 809 ft | |
| Austin, TXTexas | 2A | 30°F | 25°F | 99°F | 75°F | 542 ft | |
| El Paso, TXTexas | 3B | 25°F | 21°F | 100°F | 64°F | 3,958 ft | |
| Salt Lake City, UTUtah | 5B | 14°F | 8°F | 97°F | 63°F | 4,227 ft | |
| Burlington, VTVermont | 6A | -7°F | -13°F | 86°F | 71°F | 334 ft | |
| Richmond, VAVirginia | 4A | 18°F | 13°F | 93°F | 76°F | 167 ft | |
| Norfolk / VA Beach, VAVirginia | 4A | 24°F | 19°F | 92°F | 77°F | 26 ft | |
| Seattle (Sea-Tac), WAWashington | 4C | 28°F | 23°F | 84°F | 66°F | 429 ft | |
| Spokane, WAWashington | 5B | 3°F | -4°F | 92°F | 62°F | 2,372 ft | |
| Charleston, WVWest Virginia | 4A | 12°F | 6°F | 89°F | 74°F | 981 ft | |
| Milwaukee, WIWisconsin | 5A | -1°F | -7°F | 87°F | 73°F | 672 ft | |
| Madison, WIWisconsin | 6A | -6°F | -12°F | 88°F | 73°F | 863 ft | |
| Cheyenne, WYWyoming | 6B | -4°F | -11°F | 88°F | 58°F | 6,156 ft | |
| Toronto (Pearson), ONOntario (CA) | 5A | 1°F | -4°F | 88°F | 72°F | 568 ft | |
| Montreal (Trudeau), QCQuebec (CA) | 6A | -7°F | -13°F | 86°F | 71°F | 118 ft | |
| Vancouver (YVR), BCBritish Columbia (CA) | 4C | 25°F | 20°F | 79°F | 64°F | 14 ft | |
| Calgary, ABAlberta (CA) | 7 | -18°F | -25°F | 84°F | 59°F | 3,556 ft |
📐 Engineering Percentile Standards & Sizing Rules
Winter 99% vs 99.6% Design Dry Bulb
The 99.0% value represents the outdoor temperature exceeded 99.0% of the hours in a standard year (only 88 hours per year are colder). Standard residential Manual J heating designs use the 99% column, whereas hospitals, laboratories, and critical infrastructure use the 99.6% column.
Summer 0.4% vs 1.0% Design Dry Bulb & Coincident WB
The 0.4% design dry-bulb represents peak summer conditions exceeded only 35 hours per year. Sizing AC tonnage to the 0.4% condition ensures adequate peak capacity while avoiding excessive oversizing that impairs indoor humidity dehumidification.
IECC Climate Zones (1A to 8)
The International Energy Conservation Code (IECC) categorizes climate into moisture regimes: A (Moist/Humid), B (Dry/Arid), and C (Marine). Building envelope insulation (R-values) and HVAC efficiency tiers are mandated directly by these zones.