Manual J design temperatures by address
Winter 99 % and summer 1 % design temperatures, coincident wet bulb, daily range and grains difference for any US or Canadian address, from the ASHRAE method at the nearest station with a recent record.
Look up an address
US and Canada. Free, no account needed.
What a Manual J calculation needs from the weather
ACCA Manual J sizes heating and cooling equipment for a house from a handful of outdoor design values: the winter 99 % dry bulb (colder for only 1 % of the hours in a year), the summer 1 % dry bulb with its coincident wet bulb, the daily temperature range of the hottest month (Low, Medium or High), the grains difference between outdoor and indoor air for the latent load, and the elevation. Manual J allows its own Table 1A/1B or ASHRAE data, not a mix, and local code can name the source.
The lookup uses the ASHRAE Handbook method at the nearest station with a recent record, replicated and validated against the published ASHRAE tables (validation). Some stations in the ASHRAE list stopped recording decades ago (Denver Stapleton ended in 1995); the lookup skips those when a station with a recent record is close. For heat-pump rebates, the winter value is the temperature at which the heat pump's capacity is checked.
Design temperatures for 50 US cities
Degrees Fahrenheit. Grains: outdoor minus indoor at 75 °F and 50 % RH, at the summer design condition. City centre coordinates; a different address can use a different station.
| City | Winter 99 % | Summer 1 % | Coincident WB | Daily range | Grains | Elevation ft | Station |
|---|---|---|---|---|---|---|---|
| Anchorage, AK | -6.0 | 70.9 | 58.6 | L | -11 | 138 | Anchorage-Merrill Field Ap |
| Phoenix, AZ | 42.1 | 108.9 | 69.1 | M | -20 | 1,107 | Phoenix-Sky Harbor Intl Ap |
| Tucson, AZ | 34.9 | 102.7 | 65.5 | H | -28 | 2,549 | Tucson |
| Fresno, CA | 35.1 | 101.8 | 68.5 | H | -13 | 328 | Fresno Yosemite Intl Ap |
| Los Angeles, CA | 46.0 | 84.7 | 65.7 | L | -1 | 179 | Los Angeles Downtown-Usc Campus |
| Sacramento, CA | 34.0 | 96.8 | 67.5 | H | -11 | 26 | Sacramento Exec Ap |
| San Diego, CA | 46.9 | 81.9 | 64.9 | L | +0 | 15 | San Diego Intl Ap-Lindbergh Field |
| San Francisco, CA | 39.9 | 79.9 | 63.0 | M | -6 | 30 | Nas Alameda |
| Denver, CO | 6.3 | 91.2 | 59.2 | H | -39 | 5,663 | Aurora-Buckley Afb |
| Hartford, CT | 12.2 | 88.9 | 72.0 | M | +26 | 20 | Hartford-Brainard Ap |
| Washington, DC | 21.9 | 91.8 | 74.5 | M | +36 | 66 | Arlington-Reagan Washington Natl Ap |
| Jacksonville, FL | 39.0 | 93.7 | 75.9 | L | +42 | 20 | Nas Jacksonville-Towers Field |
| Miami, FL | 52.0 | 90.9 | 77.9 | L | +59 | 7 | Miami-Opa Locka Exec Ap |
| Tampa, FL | 46.4 | 93.0 | 78.8 | L | +61 | 8 | Tampa-O-Knight Ap |
| Atlanta, GA | 26.1 | 91.8 | 73.8 | M | +34 | 840 | Atlanta-Fulton County Ap-Brown Field |
| Honolulu, HI | 66.0 | 87.8 | 72.7 | L | +32 | 7 | Honolulu-Inouye Intl Ap Oahu |
| Chicago, IL | 6.1 | 89.4 | 72.7 | M | +30 | 623 | Chicago Midway Intl Ap |
| Indianapolis, IN | 9.0 | 88.9 | 73.6 | M | +37 | 791 | Indianapolis Intl Ap |
| Louisville, KY | 17.1 | 91.8 | 74.5 | M | +37 | 489 | Louisville Intl Ap |
| New Orleans, LA | 39.0 | 92.8 | 78.8 | L | +62 | 7 | New Orleans-Lakefront Ap |
| Boston, MA | 14.0 | 87.8 | 71.6 | L | +26 | 12 | Boston-Logan Intl Ap |
| Baltimore, MD | 21.0 | 92.8 | 74.3 | L | +33 | 20 | Baltimore Downtown |
| Detroit, MI | 10.4 | 87.8 | 71.4 | M | +26 | 626 | Detroit-Young Intl Ap |
| Minneapolis, MN | -5.1 | 87.8 | 71.2 | M | +25 | 837 | Minneapolis-St Paul Intl Ap |
| Kansas City, MO | 10.4 | 93.7 | 75.6 | M | +41 | 758 | Kansas City-Wheeler Downtown Ap |
| St. Louis, MO | 12.9 | 92.8 | 76.1 | M | +45 | 413 | Cahokia-St Louis Downtown Ap |
| Charlotte, NC | 25.0 | 91.8 | 73.8 | M | +33 | 728 | Charlotte Douglas Intl Ap |
| Raleigh, NC | 24.1 | 92.8 | 75.4 | M | +41 | 416 | Raleigh-Durham Intl Ap |
| Omaha, NE | 1.9 | 91.8 | 74.7 | M | +39 | 981 | Omaha-Eppley Af Intl Ap |
| Albuquerque, NM | 23.0 | 93.7 | 59.4 | M | -42 | 5,312 | Albuquerque Intl Sunport |
| Las Vegas, NV | 35.1 | 106.9 | 65.3 | M | -35 | 2,205 | North Las Vegas Ap |
| Buffalo, NY | 8.4 | 84.2 | 70.3 | M | +25 | 591 | Cgs Buffalo |
| New York, NY | 17.6 | 87.8 | 72.0 | L | +28 | 157 | New York-Central Park Obs-Belvedere Castle |
| Cincinnati, OH | 14.0 | 89.8 | 74.3 | M | +39 | 490 | Cincinnati Muni Ap-Lunken Field |
| Cleveland, OH | 12.0 | 85.8 | 72.5 | L | +35 | 584 | Cleveland-Burke Lakefront Ap |
| Columbus, OH | 10.9 | 88.9 | 72.3 | M | +30 | 833 | Columbus-Glenn Columbus Intl Ap |
| Oklahoma City, OK | 19.0 | 97.9 | 74.1 | M | +27 | 1,306 | Oklahoma City-Rogers World Ap |
| Portland, OR | 30.0 | 87.8 | 66.0 | M | -4 | 39 | Portland Intl Ap |
| Philadelphia, PA | 19.0 | 90.9 | 73.8 | M | +33 | 10 | Philadelphia Intl Ap |
| Pittsburgh, PA | 10.4 | 85.8 | 70.7 | M | +26 | 1,253 | Pittsburgh-Allegheny County Ap |
| Memphis, TN | 24.1 | 94.8 | 76.8 | M | +46 | 254 | Memphis Intl Ap |
| Nashville, TN | 19.9 | 92.8 | 74.5 | M | +36 | 600 | Nashville Intl Ap |
| Austin, TX | 32.0 | 99.9 | 73.9 | M | +21 | 670 | Austin-Camp Mabry Angb |
| Dallas, TX | 28.0 | 99.9 | 74.7 | M | +25 | 512 | Dallas Love Field |
| El Paso, TX | 28.9 | 99.9 | 63.3 | M | -33 | 3,918 | El Paso Intl Ap |
| Houston, TX | 35.6 | 96.6 | 76.3 | M | +40 | 226 | Houston-Dunn Heli |
| San Antonio, TX | 34.0 | 99.9 | 73.8 | M | +20 | 577 | San Antonio-Stinson Muni Ap |
| Salt Lake City, UT | 16.0 | 95.9 | 61.5 | M | -35 | 4,225 | Salt Lake City Intl Ap |
| Seattle, WA | 30.0 | 82.2 | 63.9 | M | -5 | 20 | Seattle-King County Intl Ap-Boeing Field |
| Milwaukee, WI | 3.9 | 85.8 | 71.8 | M | +31 | 692 | Milwaukee-Mitchell Intl Ap |
A PDF for the permit or rebate file
From the Manual J tool, a one-page PDF lists every value with its source station, record period and method, under your firm's name (1 credit). Load-calculation software can call the same lookup through the API.
For a full energy model rather than a load calculation, the same site gets hourly EnergyPlus weather files (EPW) with DDY design days: typical years, actual years and future climate.
Frequently asked questions
What is the winter 99 % design temperature?
The outdoor dry bulb that is colder for only 1 % of the hours in a year (about 88 hours). Manual J uses it to size heating equipment and heat pumps.
Which summer values does Manual J use?
The 1 % dry bulb (warmer for 1 % of the hours) and the mean coincident wet bulb at that temperature, plus the daily range class of the hottest month and the grains difference for the latent load.
Where do the values come from?
The ASHRAE Handbook method applied to the nearest station with a recent record, replicated from NOAA hourly data and validated against the published ASHRAE tables.
Can I use these for a permit?
Manual J accepts ASHRAE outdoor design data; your jurisdiction or rebate programme can require a specific source. The PDF names the station, period and method so a reviewer can check it.
Does it cover Canada?
Yes. Addresses in the US and Canada are geocoded; any coordinates work through the tool and the API.
Need the PDF for the file?
Free to try, no credit card.
Open the Manual J tool →