Original analysis of NOAA and Census data
Columbia heat data: what summer asks of an air conditioner
56 full years of daily highs and lows from Columbia Regional Airport show the area now averaging 42.7 days of 90°F heat and 37.3 nights with a low of 70°F or more. The 1991-2020 baseline was 34.4 and 27.8.
Days per year at 90°F or hotter, Columbia Regional Airport
Nights per year when the low stayed at 70°F or above
Eight things the record shows
- Hot afternoons are up. The 1991-2020 baseline was 34.4 days a year at 90°F or above; 2016-2025 averaged 42.7; the 6 complete years of the 2020s average 40.8. Days reaching 95°F climbed from 10 to 12.
- Nights cool off less. Lows of 70°F or warmer rose from 27.8 a year to 37.3, and lows of 75°F or warmer from 3.5 to 5.9.
- The hot season stretched. In 2016-2025 the year's first 90°F reading typically came about June 2 and the last about September 24, a span near 114 days. The 1991-2020 span ran June 11 to September 11, close to 92 days.
- July carries the load. It averages roughly 15 days of 90°F heat, with June and August near 10 apiece and September near 6.
- Winter still bites. Lows of 10°F or colder came 9.8 times a year in 2016-2025, down from 11.8 in 1991-2020. The record low is -20°F, set December 22, 1989. Any heat pump here lives with both extremes.
- The extremes. Since 1970 the top reading is 111°F, on July 30, 1980. The longest unbroken string of 90°F days was 27, ending July 21, 1980. The mildest night bottomed out at 84°F on July 10, 1980.
- This year. As of October 24, 2026, 2026 had 44 days at 90°F or more, where the 1991-2020 baseline would expect 34.4 by now. It peaked at 100°F on September 5, 2026, last touched 90°F on October 13, 2026, and had 45 nights with lows of 70°F or above.
- Wet summers. Yearly rain at the airport averages 41.42 inches (1991-2020), 31% of it between May and July. That damp air is the reason a Boone County system spends so much effort drying the house, not only cooling it.
Average days at 90°F or hotter, by month
Nights per year at 10°F or colder, Columbia Regional Airport
By decade
| Decade | Days at 90°F+ per year | Days at 95°F+ per year | Nights at 70°F+ per year | Nights at 10°F or colder |
|---|---|---|---|---|
| 1970s | 35.7 | 8.8 | 20.9 | 20.6 |
| 1980s | 39.8 | 14.8 | 28.0 | 17.8 |
| 1990s | 31.2 | 7.1 | 23.3 | 12.1 |
| 2000s | 30.2 | 9.8 | 23.2 | 11.8 |
| 2010s | 41.5 | 13.6 | 35.8 | 12.0 |
| 2020 to 2025 | 40.8 | 12.0 | 35.7 | 9.8 |
Housing, ZIP by ZIP
The older the housing, the likelier the ductwork predates the cooling equipment it now serves. The electric heat column flags the homes where a heat pump is the natural next system.
| ZIP | Area | Housing units | Median year built | Built before 1980 | Built 2000 or later | Owner occupied | Electric heat |
|---|---|---|---|---|---|---|---|
| 65203 | West and South Columbia | 27,520 | 1991 | 34% | 33% | 62% | 35% |
| 65201 | Central and East Columbia | 21,289 | 1990 | 34% | 36% | 32% | 58% |
| 65202 | North Columbia | 20,425 | 1993 | 31% | 40% | 63% | 41% |
| 65233 | Boonville | 4,628 | 1973 | 60% | 18% | 70% | 49% |
| 65240 | Centralia | 3,821 | 1985 | 46% | 23% | 80% | 38% |
| 65010 | Ashland | 3,111 | 2002 | 21% | 55% | 77% | 44% |
| 65255 | Hallsville | 2,011 | 1995 | 33% | 43% | 80% | 42% |
| 65248 | Fayette | 1,784 | 1967 | 59% | 23% | 69% | 27% |
| 65039 | Hartsburg | 1,250 | 1991 | 35% | 28% | 96% | 54% |
| 65284 | Sturgeon | 1,095 | 1979 | 52% | 26% | 79% | 41% |
| 65256 | Harrisburg | 974 | 1990 | 39% | 31% | 91% | 44% |
| 65279 | Rocheport | 930 | 1982 | 48% | 21% | 88% | 33% |
| 65254 | Glasgow | 919 | 1966 | 67% | 19% | 86% | 37% |
| 65274 | New Franklin | 861 | 1974 | 60% | 13% | 78% | 42% |
The area label is our own shorthand for the biggest town or neighborhood in each ZIP. Figures are Census ACS 2020-2024 5-year estimates from tables B25034, B25035, B25003 and B25040. Tap a header to re-sort.
Method and caveats
Weather. Daily summaries from NOAA NCEI's Global Historical Climatology Network for station USW00003945 at Columbia Regional Airport, covering November 1, 1969 through October 24, 2026. We kept only years with both a high and a low on 355 or more days, leaving 56 years (1970-2025). Our "baseline" is the 1991-2020 average and "recent" is 2016-2025. We tallied these ourselves from the daily file; they are not NOAA's published climate normals.
Housing. American Community Survey 2020-2024 5-year estimates at the ZIP Code Tabulation Area level, pulled through Census Reporter, for Columbia's three ZIPs plus the nearby towns in Boone, Cooper and Howard counties.
Caveats. The airport sits south of Columbia, near Ashland, and a single station can't speak for every block; this dataset also has no humidity readings. Downtown nights can stay warmer than the airport's. Read these numbers as a portrait of the area, never as a diagnosis of one house.
Reuse. Reporters, home inspectors and anyone else may cite or reproduce the charts and tables under CC BY 4.0, linking back here.