In brief: After a pair of almost fall-like weather days, Houston’s pattern will tilt back toward summer. As high pressure asserts control our forecast looks to be locked in for pretty much the next 10 days: hot days, lots of sunshine, and virtually no chance of rain.

High pressure in September

When it comes to weather, most people understand that low pressure equates to the potential for stormy conditions, whereas high pressure creates a more stable atmosphere with sinking air. At most times of year when we see high pressure (sinking air) this leads to mostly sunny or cloudless days. This can feel fantastic in February or March, but decidedly sultry and hot in July and August.

By the middle of September we are starting to edge toward fall, with shorter days and a lower Sun angle, high pressure hits a little bit different. Instead of high temperatures of 100 degrees like in August, we are likely to see highs generally in the mid-90s. Instead of lows around 80 degrees, we are likely to see low- to mid-70s. Dewpoints should be 5 to 10 degrees lower which means the air will feel slightly less humid than peak summer.

So for those who want a little bit more summer, you’re in luck. For those pining for fall after the last couple of days, it’s going to be a loooong week, at least.

Wednesday

It is another pleasantly cool morning across the region, with the usual spots such as Conroe dipping into the upper 50s and much of Houston in the mid-60s this morning. Alas, all good things must end. Winds will turn easterly today, increasing an onshore flow, and starting to increase humidity levels. For the most part I think highs today will remain in the low- to mid-90s, with sunny skies. Lows tonight will only drop into the mid-70s, so about 10 degrees warmer for most locations. With light winds today, conditions are favorable for producing elevated levels of ozone. An Ozone Action Day is in effect.

Thursday through Sunday

Each of these days is going to be very, very similar. We can expect mostly sunny to cloudless days with highs in the low 90s near the coast and mid-90s for most of the rest of the area. Some far inland locations may push into the upper 90s. Most days will have modest southeasterly winds at about 10 mph. Nights will be in the mid-70s. Rain chances will be essentially zero. If you have outdoor plans our confidence in this forecast is very high.

Next week

Not much changes for at least the first half of next week: same skies, same temperatures, similar humidity. Rain chances are low through at least Wednesday or Thursday, by which time coastal areas may start to see some isolated showers. Really, I don’t see any real spark of change in this pattern until at least next weekend, and maybe not then.

Atlantic tropics

Today is the historical peak of the Atlantic hurricane season. Yet this year, there is precisely nothing to talk about. That is ideal!

In brief: It’s officially Fall Day in Houston, with the season’s first 65-degree temperature reading this morning. We are also excited to announce that we’ll be holding our Fall Day Celebration on October 25 in Houston. More details in today’s post, which discusses our largely unchanging weather for the next 10 days. We also talk tropics.

Fall Day celebration

The temperature at Houston’s official weather station, Bush Intercontinental Airport, fell to 65 degrees this morning (and it currently has reached 64, as of 6:20 am). That means we can officially declare today as “Fall Day” in Houston. If you’re unfamiliar with this little tradition, it’s simply the day when we get our first real taste of fall in the city after a long summer.

Speaking of this, I’m excited to announce that we are planning a special Fall Day Celebration for Saturday, October 25. This year’s event will also commemorate the 10th anniversary of Space City Weather. This year we are gathering at Midtown Park from 10 am to Noon. We will have more information soon, but rest assured we are planning a special event for you and your families. Come celebrate with us!

Tuesday

This deligtfully dry air will persist today and tonight before a more easterly flow starts to raise humidity. As a result we can expect sunny skies today, with high temperatures around 90 degrees. With dewpoints in the 50s, this afternoon will like Monday bring a somewhat dry heat into the area. This evening will be pleasant. Lows tonight will drop to around 70 degrees in Houston, with cooler conditions further inland.

Wednesday through the weekend

As high pressure builds from the west, I don’t expect much variability in our weather for the remainder of the week. Each day should bring sunny skies and high temperatures in the low 90s in Houston, with areas further inland (i.e. Katy and The Woodlands) likely pushing into the mid-90s. Dewpoints will be in the 60s, generally, so while the air will be more humid, it won’t be the super sticky humidity we see during summertime in Houston.

Lows will generally fall into the low- to mid-70s. Rain chances throughout this period will basically be zero, except for the immediate coast, which might see slightly higher chances (i.e. 10 or 20 percent) on some afternoons.

Next week

This pattern has to change at some point, right? Well, eventually. Mostly, however, I expect it to persist into at least the middle of next week. At that point rain chances may tick up slightly, but I don’t see any evidence of the next front at this time. So after today it will be late summertime weather for awhile.

Atlantic tropics

It’s very quiet there for what is typically the peak of the Atlantic hurricane season. We have zero concerns at this point. When we look out for the next 10 days, conditions look to be fairly quiet. The sub-seasonal forecast from the European model, shown above, predicts significantly less activity than normal in the Atlantic basin (40 percent of normal). By the last 10 days of the month this model is back to predicting near-normal activity in the Atlantic, and overall conditions should improve. But long-time readers of Space City Weather will know that our window for seeing a hurricane landfall in the greater Houston region is closing. I’m certainly not ready to declare the season “over” for Texas, but we are just weeks away from that happening. So we’re in the home stretch.

In brief: In today’s post we talk about the region’s flirtations with fall, and we are going to have a couple of very fine days with cooler nights. But after this a warmer and somewhat more humid pattern returns, although we are beyond the worst of summer. Dwight also checks in with an update on our app!

Fall’s first front

A decent front has pushed offshore, and we are seeing rather dry air move into the region. As as result humidity will feel decently low today and Tuesday. The big question for me is, will we hit 65 degrees tonight? It’s going to be close. That is our arbitrary definition of the first fall-like weather in the city. Since the city’s official station moved to Bush Intercontinental Airport in 1969, the average date of the first 65-degree (or cooler) night has been September 12, so we’re close to that time of year. Regardless, it will feel notably cooler tonight than we have experienced since May 12.

Final app update🤞🏻for 2025

(The following update comes from Dwight). As summer fades, so does our annual development push for the Space City Weather app. Over the past couple of months, developer Hussain Abbasi has been cranking away on updates for the Apple and Android versions, smashing bugs and tuning the apps for performance. We think both are in a good place right now, and pending any undiscovered issues, we’re happy. We hope you are, too!

And you appear to be, because over the past few weeks, the number of bug reports we’ve received have dwindled to near-nil. Thanks to everyone who used the Send Feedback button in the app to make those reports. They help!

And as part of our new Discourse platform, which handles blog comments in a forum setup, we have added a new category: App Feedback. Got comments, questions, concerns or feature requests? App Feedback is the place to leave them. In addition, we’ve got an initial post which serves as a mini FAQ about the SCW app, with a few Good Things to Know™ as well as instructions for filing a bug report. Please give it a read before posting in this new forum category, because there’s a good chance your question is already answered there.

As always, thanks for downloading and using the app!

Monday

Today will be sunny and warm, with a high temperature in the upper 80s to 90 degrees for the metro area, with a northeast wind of about 10 mph. I highly recommend planning to spend this evening outdoors because it is going to be lovely, with mild temperatures and drier air. Seriously, this is porch weather. I don’t have a great handle on how low temperatures will go tonight, but I think Houston will fall into the upper 60s, with inland areas dropping into the lower 60s to upper 50s.

Tuesday

This will be another day with reasonably dry air. Expect sunny skies and highs around 90 degrees. As winds shift to come from the east humdity will start to come up a little. Still, I expect Houston to see lows around 70 degrees with inland areas dropping into the 60s on Tuesday night.

Wednesday, Thursday, and Friday

We return to a more summer-like pattern for the rest of the week as high pressure starts to build. However since we’re now approaching mid-September, this means highs generally in the low- to mid-90s, with nights in the mid-70s. Dewpoints will be high, but not opppressively so. So hot, yes. But super hot, no (see, for example, the wet bulb globe temperatures in the graphic above). Expect sunny skies and no rain.

Saturday and Sunday

The weekend looks the same: Sunny skies, highs in the low- to mid-90s, with a fair but not exessive amount of humidity. Rain chances appear to be close to zero through the weekend.

Next week

This pattern of highs in the low- to mid-90s should persist into next week as late summer holds on. Some rain chances may finally return to the forecast about 10 days from now.

The Atlantic tropics

Things are surprisingly quiet right now for September, with zero threats in the Atlantic. We only have a few weeks left of “prime time” for storms in Texas. Tomorrow I’ll take a look at what may happen during that time.

In brief: Houston will see more humid weather this weekend with rain chances re-entering the forecast slightly today and tomorrow and more so on Sunday as a weak front approaches. Though locally heavy rain is possible, we don’t expect widespread heavy rainfall. Temperatures will be warm by day and cooler again by night early next week before a late summer hurrah arrives again after Tuesday or Wednesday.

Programming note

If you live or work in the City of Houston, you are going to receive a test emergency alert this morning at 11 AM. It will look like an Amber Alert, except it will read “TEST Wireless Emergency Alert from the City of Houston Office of Emergency Management: No Action Required. TEST ALERT. For more information visit HoustonOEM.org.” The test is meant to only go out to anyone in Houston at that time, though because it’s targeted to specific cell towers, you may be in an adjacent location and still receive it as well.

Tests like this are necessary periodically to ensure the system works properly. WEA cell alerts have been a source of, shall we say, consternation in recent years for a number of reasons. They’re well-intentioned but in some cases not always relevant. Ignoring the broader conversation around those sorts of public safety alerts, we will note that weather alerts are quite relevant. Only higher end flash flood warnings will get pushed to your phone. I think this topic takes on some renewed relevance in the wake of the July 4th Hill Country tragedy, something we can discuss more another day. If you’ve turned them off in the past and want to turn them back on:

iPhone:
Go to Settings > Notifications, scroll to the bottom under Government Alerts, and you can turn on Emergency Alerts there.

Android:
Go to Settings > Safety & Emergency > Wireless Emergency Alerts, and you can enable Allow Alerts.

Anyway, we just wanted to make sure you knew that was coming today.

Today

I’m not sure if anyone else felt this way, but yesterday seemed really nice. We had very few clouds and generally tolerable humidity, although it was fairly hot by late afternoon. It sort of “looked” like a change of seasons was slowly beginning.

Of course, humidity is notably higher already this morning, so that autumn thinking may be short-lived. Expect a similar day overall: Sun, a few clouds, and highs in the mid-90s, possibly upper-90s — but with more humidity than yesterday. An isolated shower or storm could pop up this afternoon as the sea breeze moves inland, but most folks should stay dry.

Weekend

There has been some discussion around Lorena in the Pacific and how it may fling some higher moisture in our direction later this weekend. Well, Lorena’s forecast has changed significantly in the last couple days. It’s now post-tropical, and it’s expected to make a U-turn back out into the Pacific. While overall atmospheric moisture increases this weekend, the threat for any significant heavy rainfall has come off some.

Expect at least isolated thunderstorms Saturday and more scattered to perhaps even numerous storms on Sunday as another (!) front approaches. Locally heavy rainfall could occur, but widespread, significant rain is unlikely. Still, if you’ve got outdoor plans this weekend, just consider a backup in case a downpour passes by. Highs will be in the upper-80s to low-90s due to clouds, with high humidity.

Next week

With drier air filtering in behind the front next week, we will probably see low temperatures drop back into the low-70s or even upper-60s in spots. High temps will likely remain rather hot in the low to mid-90s. Our autumn fling will probably end after early next week, as high pressure tries to build and expand over the Southern Plains. Better now than in July or August, I suppose.

Whatever the case, look for a late summer hurrah beginning after midweek next week.