Maryland design temperatures
Outdoor heating and cooling design conditions for 3 Maryland weather stations. Choose the station nearest to you in distance and elevation, and check whether your building department specifies its own values.
| Station | Elevation | 99.6 % heating | 99 % heating | 1 % cooling / MCWB | 0.4 % cooling / MCWB | Use it |
|---|---|---|---|---|---|---|
| Andrews AFBWMO 745940 · 1967–1996 | 282 ft | 13 °F | 17 °F | 90 / 74 °F | 93 / 75 °F | Load calculator |
| Baltimore/WashingtonWMO 724060 · 1973–1996 | 154 ft | 12 °F | 16 °F | 91 / 74 °F | 94 / 76 °F | Load calculator |
| Patuxent River NASWMO 724040 · 1967–1996 | 39 ft | 15 °F | 20 °F | 89 / 75 °F | 92 / 76 °F | Load calculator |
Using these values
- Heat-loss calculations for homes commonly use the 99 % heating value, and cooling loads the 1 % dry bulb with its mean coincident wet bulb (MCWB). The 99.6 % and 0.4 % values are more conservative.
- “Load calculator” opens the heating and cooling load calculator with that station’s 99 % and 1 % temperatures and its design moisture difference (outdoor air at the 1 % condition versus 75 °F, 50 % RH indoors, at the station’s elevation).
- Source: U.S. Air Force Combat Climatology Center and NOAA National Climatic Data Center, Engineering Weather Data (1999; public domain). Each station’s period of record is shown under its name; they end by 1996, and the climate has warmed since, so check local requirements before relying on a value for a permit.