Autumn Begins on September 22, but Houston Will Stay in the 90s °F
Updated September 20, 2026.
HOUSTON, Texas — Astronomical autumn begins in Houston on Tuesday, September 22 at 7:05 p.m. CDT, but the seasonal change will not bring immediate cold. Temperatures will continue to reach the 90s °F in the coming days.
The cold in Houston does not start on a single date. October tends to mark the most evident shift after summer, when nights begin to cool and cold fronts can cause temporary drops. In November, cool temperatures appear with much greater frequency.
September still behaves like a hot month. The normal maximum is 90.4 °F (32.4 °C) and the minimum is 70.6 °F (21.4 °C), according to the 1991-2020 climate normals for Houston.
When does it start to cool down in Houston?
- September 22: astronomical autumn begins in 2026, but temperatures will remain in the 90s °F.
- October: more noticeable changes begin and fronts can bring fresh mornings.
- November: cool temperatures become much more frequent.
- December: normal lows are already in the 40s °F and cold episodes increase.
- January: is normally the coldest month of the year in Houston.
Autumn Starts on September 22, but Houston Will Remain in the 90s °F
The meteorological autumn began on September 1. The astronomical autumn, defined by the equinox, will begin on September 22 at 7:05 p.m. CDT.
None of these dates alone marks the start of cold weather in Houston.
For the week of the equinox, the National Weather Service keeps highs in the 90s °F for Houston. Temperatures could reach the mid to upper 90s during the first days of the week before decreasing toward the lower 90s as the weekend approaches.
Low temperatures will also remain mainly in the 70s °F. For now, the forecast does not show a sustained transition to cold conditions.
September Maintains a Normal High of 90.4 °F
The 1991-2020 climate normals show an average temperature of 80.5 °F (26.9 °C) during September.
The average monthly high is 90.4 °F and the average low is 70.6 °F. Therefore, even after the equinox, hot afternoons remain normal during this part of the year.
The arrival of autumn on the calendar does not prevent hotter episodes. Houston can maintain summer-like temperatures until the end of September and even into parts of October.
October Lowers Houston’s Normal Low to 60.9 °F
October marks the first major monthly change from summer.
The normal high drops to 82.8 °F (28.2 °C), almost 8 degrees cooler than in September. The average low falls by about 10 degrees, to 60.9 °F (16.1 °C).
Cold fronts also begin to have greater impact on Southeast Texas during this autumn stage. Some can push temperatures well below the monthly averages for one or more days.
However, a cool morning in October does not necessarily mean the heat is finished. Houston can quickly return to warm afternoons after a front passes.
That change can happen rapidly: a cold front can take Houston from near 90 °F to lows in the 50s °F in a few hours.
November Brings Normal Lows Near 50 °F
November offers a clearer answer for those who associate the beginning of cold with markedly cooler mornings and evenings.
The normal high for the month is 72.6 °F (22.6 °C) and the low drops to 51.5 °F (10.8 °C).
Temperatures continue to decrease as the month progresses, although Houston can alternate cooler days with warmer periods even during November.
The difference between September and November is considerable: the normal high decreases by almost 18 degrees and the low by more than 19 degrees.
December and January Concentrate the Lowest Temperatures
The conditions closest to winter appear more regularly starting in December.
The normal high of December is 65.3 °F (18.5 °C) and the low is 45.6 °F (7.6 °C).
January is normally the coldest month of the year in Houston, with an average temperature of 53.8 °F. The average high is 63.8 °F (17.7 °C) and the average low is 43.7 °F (6.5 °C).
Houston can also record much colder episodes than these averages. Arctic fronts can push parts of the metropolitan area to freezing or below, but those events do not represent typical winter conditions.
Normal Temperatures Drop Almost 27 Degrees from September to January
| Month | Average High | Average Low |
|---|---|---|
| September | 90.4 °F / 32.4 °C | 70.6 °F / 21.4 °C |
| October | 82.8 °F / 28.2 °C | 60.9 °F / 16.1 °C |
| November | 72.6 °F / 22.6 °C | 51.5 °F / 10.8 °C |
| December | 65.3 °F / 18.5 °C | 45.6 °F / 7.6 °C |
| January | 63.8 °F / 17.7 °C | 43.7 °F / 6.5 °C |
Between September and January, Houston’s monthly normal high decreases by 26.6 degrees Fahrenheit, while the low falls by 26.9 degrees.
A First Cold Front Does Not Mark the Final End of the Heat
The arrival of the first cold front and the start of a season with consistently cooler temperatures are two different moments.
A front can push drier, cooler air into Southeast Texas and cause a rapid drop in temperatures. After it passes, winds can shift and allow warm, humid air from the Gulf to return.
For that reason, Houston can experience a morning in the 50s or 60s °F during autumn and then again have considerably warmer afternoons.
October Marks the Transition and November Brings Cold More Frequently
To practically answer when the cold begins in Houston, October is normally the transition month. Nights begin to cool and fronts can generate the first significant declines.
November is when the cool weather becomes much more frequent, with average lows near 50 °F. December and January then bring the year’s lowest normal temperatures.
The National Weather Service’s climate normals for Houston allow comparing the average temperatures for each month and distinguishing those seasonal changes from an isolated cold front.
The September 22 equinox officially begins the 2026 astronomical autumn, but the forecast temperatures for Houston will remain in the 90s °F in the following days. The seasonal shift tends to become much more evident during October.
