New Mexico climate zones and HVAC design temperatures
New Mexico spans 3 IECC climate zones. 44% of people live in zone 4B (mixed, dry). In Albuquerque, heating and cooling equipment is sized for 94°F in summer and 23°F in winter.
Design temperatures for major cities
| City | Zone | Summer 1% | Winter 99% | Water in |
|---|---|---|---|---|
| Albuquerque | 4B | 94°F | 23°F | 61°F |
| Las Cruces | 3B | 100°F | 27°F | 66°F |
| Santa Fe | 5B | 92°F | 16°F | 55°F |
| Roswell | 3B | 102°F | 23°F | 65°F |
| Farmington | 5B | 95°F | 15°F | 56°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: 102°F (Chaves County); coldest winter design: 5°F (Taos County).
Typical equipment sizes in Albuquerque
One-story house with average insulation (R-13 walls, R-30 attic, double-pane windows), at Albuquerque'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 tons | 40,000 BTU | 2 tons + 5 kW backup |
| 2,000 sq ft | 2.5 tons | 40,000 BTU | 2.5 tons + 5 kW backup |
| 2,500 sq ft | 3 tons | 40,000 BTU | 3 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 3B: warm, dry (8 counties, 25% of people)
| County | Summer 1% | Winter 99% |
|---|---|---|
| Chaves County | 102°F | 23°F |
| Doña Ana County | 100°F | 27°F |
| Eddy County | 101°F | 23°F |
| Hidalgo County | 94°F | 23°F |
| Lea County | 99°F | 21°F |
| Luna County | 99°F | 24°F |
| Otero County | 99°F | 25°F |
| Sierra County | 98°F | 27°F |
Zone 4B: mixed, dry (13 counties, 44% of people)
| County | Summer 1% | Winter 99% |
|---|---|---|
| Bernalillo County | 94°F | 23°F |
| Catron County | 90°F | 14°F |
| Cibola County | 90°F | 11°F |
| Curry County | 96°F | 18°F |
| De Baca County | 97°F | 19°F |
| Grant County | 94°F | 23°F |
| Guadalupe County | 99°F | 17°F |
| Lincoln County | 86°F | 19°F |
| Quay County | 99°F | 17°F |
| Roosevelt County | 96°F | 18°F |
| Socorro County | 97°F | 23°F |
| Union County | 94°F | 13°F |
| Valencia County | 94°F | 23°F |
Zone 5B: cool, dry (12 counties, 31% of people)
| County | Summer 1% | Winter 99% |
|---|---|---|
| Colfax County | 90°F | 9°F |
| Harding County | 99°F | 17°F |
| Los Alamos County | 85°F | 18°F |
| McKinley County | 92°F | 9°F |
| Mora County | 88°F | 13°F |
| Rio Arriba County | 85°F | 18°F |
| San Juan County | 95°F | 15°F |
| San Miguel County | 88°F | 13°F |
| Sandoval County | 94°F | 23°F |
| Santa Fe County | 92°F | 16°F |
| Taos County | 87°F | 5°F |
| Torrance County | 87°F | 14°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.