Original analysis of NOAA and Census data
Mesa heat data: how hard summer is on an air conditioner
Sky Harbor now averages 36.5 days a year at 110°F or hotter and 18.8 nights that never cool below 90°F, based on 84 years of daily readings. Both are far above the 1991-2020 averages of 20.8 and 7.4. Mesa's Falcon Field runs a few degrees cooler at night, and still sees about 7 of those nights a year.
Days per year at 110°F or hotter, Phoenix Sky Harbor
Nights per year when the low stayed at 90°F or above
What we found
- More 110 degree days. 20.8 a year in 1991-2020, 36.5 in 2016-2025, and 43.2 a year so far in the 2020s (6 complete years). Days at 100°F or more went from 111.3 to 119.9.
- Nights that never cool off. Sky Harbor didn't record a single night with a low of 90°F or more until July 16, 1970. It averaged 7.4 a year in 1991-2020 and 18.8 in 2016-2025. 2024 had 39. Nights at 80°F or more went from 74 a year to 84.5.
- Mesa is a little cooler, not cool. On the same dates, 2019-2025, Falcon Field averaged 20.3 days a year at 110°F or more (Sky Harbor 41.1) and 7 nights at 90°F or warmer (Sky Harbor 22.4). Summer lows at Falcon Field ran about 2.6°F below the airport.
- A longer season. Over 2016-2025 the first 100°F day came around April 27 on average and the last around October 7, about 164 days apart. In 1991-2020 it was May 3 to October 5.
- Records: the hottest reading since 1934 was 122°F on June 26, 1990. The longest run of 100°F days was 113 in a row, ending September 16, 2024, and the longest run of 110°F days was 31, ending July 30, 2023. The warmest night had a low of 97°F, first on July 19, 2023.
- 2026 so far: 131 days at 100°F or more through October 24, 2026, against a 1991-2020 average of 111.3 by that date. 39 days reached 110°F and 29 nights stayed at 90°F or above. The high for the year was 117°F on July 24, 2026.
- Monsoon: July through September bring 33% of Sky Harbor's average yearly rain (1991-2020), along with dust storms, humidity and power cuts.
Mesa Falcon Field and Sky Harbor, side by side
| Average per year, 2019-2025 | Mesa Falcon Field | Phoenix Sky Harbor |
|---|---|---|
| Days at 100°F or hotter | 103.7 | 123.3 |
| Days at 110°F or hotter | 20.3 | 41.1 |
| Nights at 80°F or warmer | 74.3 | 87.7 |
| Nights at 90°F or warmer | 7 | 22.4 |
Same dates at both stations, 2019-2025 (2,531 days with a high and low at both). NOAA NCEI daily summaries, stations USW00003185 and USW00023183.
Average days at 110°F or hotter, by month
Average daily high and low by month, Phoenix Sky Harbor
By decade
| Decade | Days at 100°F+ per year | Days at 110°F+ per year | Nights at 80°F+ per year | Nights at 90°F+ per year |
|---|---|---|---|---|
| 1950s | 85.8 | 8.4 | 26.1 | 0.0 |
| 1960s | 88.6 | 10.3 | 24.1 | 0.0 |
| 1970s | 100.8 | 17.0 | 46.5 | 0.7 |
| 1980s | 111.2 | 19.0 | 66.3 | 2.2 |
| 1990s | 102.8 | 13.6 | 63.1 | 2.2 |
| 2000s | 114.6 | 22.1 | 77.4 | 7.1 |
| 2010s | 111.4 | 23.8 | 78.7 | 10.6 |
| 2020 to 2025 | 126.7 | 43.2 | 89.2 | 24.2 |
Homes by ZIP code
Older housing tends to mean older ducts and systems that were replaced piecemeal. Mobile and manufactured homes usually run packaged units. Heating fuel shows which homes already rely on electric heat, where a heat pump is the usual replacement.
| ZIP | Area | Housing units | Median year built | Built before 1980 | Built 2000 or later | Mobile homes | Owner occupied | Electric heat |
|---|---|---|---|---|---|---|---|---|
| 85142 | Queen Creek | 29,983 | 2010 | 4% | 89% | 2% | 88% | 47% |
| 85225 | Chandler (east central) | 29,243 | 1991 | 21% | 26% | 6% | 62% | 72% |
| 85204 | Mesa (south central) | 24,537 | 1980 | 49% | 12% | 10% | 58% | 78% |
| 85205 | East Mesa (Superstition Springs north) | 23,590 | 1986 | 29% | 21% | 24% | 73% | 87% |
| 85207 | Northeast Mesa (Las Sendas, Usery) | 23,001 | 2001 | 13% | 52% | 16% | 83% | 73% |
| 85201 | Mesa (west central, downtown) | 22,779 | 1981 | 46% | 13% | 7% | 39% | 84% |
| 85209 | Southeast Mesa (Superstition Springs) | 22,295 | 2001 | 7% | 53% | 20% | 73% | 64% |
| 85224 | Chandler (north) | 21,530 | 1989 | 17% | 20% | 1% | 54% | 85% |
| 85295 | Gilbert (southeast) | 20,782 | 2007 | 2% | 85% | 0% | 63% | 50% |
| 85248 | Chandler (Sun Lakes, Ocotillo) | 20,190 | 1997 | 10% | 42% | 3% | 78% | 59% |
| 85206 | East Mesa (south of US 60) | 19,109 | 1988 | 26% | 23% | 12% | 64% | 81% |
| 85296 | Gilbert (central) | 18,839 | 2001 | 4% | 54% | 0% | 69% | 55% |
| 85286 | Chandler (south central) | 18,765 | 2006 | 3% | 74% | 2% | 65% | 47% |
| 85208 | East Mesa (Signal Butte) | 18,609 | 1989 | 30% | 25% | 38% | 82% | 81% |
| 85234 | Gilbert (north) | 18,347 | 1994 | 8% | 24% | 1% | 76% | 68% |
| 85202 | Mesa (southwest, Dobson Ranch) | 18,154 | 1979 | 54% | 10% | 3% | 51% | 89% |
| 85212 | Southeast Mesa (Eastmark, Gateway) | 18,043 | 2011 | 4% | 86% | 2% | 84% | 39% |
| 85249 | Chandler (southeast) | 17,767 | 2005 | 1% | 83% | 2% | 89% | 37% |
| 85120 | Apache Junction (south) | 17,526 | 1991 | 23% | 30% | 53% | 82% | 78% |
| 85226 | Chandler (west) | 17,435 | 1992 | 5% | 18% | 0% | 61% | 80% |
| 85140 | San Tan Valley (north) | 17,208 | 2008 | 4% | 91% | 6% | 86% | 53% |
| 85210 | Mesa (central, Fiesta District) | 16,235 | 1983 | 42% | 16% | 4% | 43% | 91% |
| 85143 | San Tan Valley (south) | 15,999 | 2007 | 1% | 94% | 2% | 80% | 59% |
| 85233 | Gilbert (west) | 15,711 | 1994 | 8% | 17% | 0% | 73% | 72% |
| 85213 | Mesa (north, Lehi) | 15,223 | 1988 | 28% | 25% | 23% | 79% | 81% |
| 85298 | Gilbert (Seville, south) | 15,058 | 2009 | 2% | 93% | 0% | 91% | 32% |
| 85203 | Mesa (north central) | 14,112 | 1979 | 53% | 10% | 4% | 57% | 83% |
| 85119 | Apache Junction (north) | 13,692 | 1994 | 16% | 33% | 38% | 80% | 90% |
| 85297 | Gilbert (south) | 12,160 | 2007 | 2% | 88% | 0% | 75% | 48% |
| 85118 | Gold Canyon | 9,415 | 2002 | 4% | 61% | 15% | 92% | 63% |
| 85215 | Northeast Mesa (Red Mountain) | 9,243 | 1993 | 16% | 22% | 17% | 80% | 78% |
Area names are our shorthand for the main neighborhood or town in each ZIP. Census ACS 2020-2024 5-year estimates (tables B25034, B25035, B25024, B25003, B25040). Click a column to sort.
How we built this
Temperature. NOAA NCEI Global Historical Climatology Network daily summaries for Phoenix Sky Harbor International Airport (station USW00023183), June 1, 1933 to October 24, 2026. A year counts only if it has a high and low on at least 355 days, which leaves 84 complete years (1934-2025). "Normal" here means the average of 1991-2020; "recent" means 2016-2025. These are our own counts from the daily record, not NOAA's official normals.
Mesa. Mesa Falcon Field (station USW00003185) reports from October 2018. We compared it with Sky Harbor on the same dates in 2019-2025, the years Falcon Field has a high and low on at least 340 days.
Homes. US Census American Community Survey 2020-2024 5-year estimates by ZIP Code Tabulation Area, via Census Reporter.
Limits. Two stations don't describe every neighborhood. The foothills toward Las Sendas and Gold Canyon sit several hundred feet higher than either station. Use this to understand the area, not to diagnose your system.
Using this data. Journalists and inspectors are welcome to cite or republish these charts and tables with a link to this page (CC BY 4.0).