Month: September 2025

In brief: In today’s post we talk about the impact of early season fronts along the Gulf coast, which are somewhat paradoxical. We also look ahead to increasing rain chances due to a front and potentially moisture from a tropical system in the Pacific Ocean.

The paradox of early season fronts

From a practical standpoint, it’s really a misnomer to call the first fronts of late summer and early fall “cold fronts.” In a strictly meteorological sense, they are. But when these early fronts usher in drier air and clearing skies (but not much cooler air) they make it more efficient for the lower atmosphere to heat up. And that’s what we are going to see over the next couple of days: sunshine, hottish days with lower humidity, and mild nights. In fact, some locations north and west of Harris County may dip into the upper 60s tonight. That is not “cold,” but it is a nice departure from very humid nights we’ve experienced since June. It’s also a foretaste of what is to come in a few weeks, when we should see some stronger fronts trundling down into the area.

Wednesday

As a slightly drier air mass moves into place today we will see highs, generally, in the mid-90s across the region. We cannot rule out a slight chance of showers for areas south of Interstate 10 later this afternoon, with daytime heating, but most of us should remain dry. Skies, otherwise, will be sunny with a light northwest wind in place. Lows tonight will drop into the low- to mid-70s in Houston, with cooler conditions in place for areas further inland.

Thursday and Friday

With a drier air mass in place we can expect sunny days with hot temperatures in the mid-90s in Houston, and upper-90s for areas further inland. Nights will drop into the 70s for most of the region. The air will be a little drier, but not crazily so.

Saturday and Sunday

By later on Friday we should see the resumption of an onshore flow that will increase atmospheric moisture levels. This will generate some clouds, and lower daytime temperatures, likely in the lower 90s on Saturday and pushing us into the upper 80s on Sunday. There are a couple of things we just don’t know enough about that will drive rain chances and amounts this weekend. First up is a slow-moving front that will be pushing toward (and possibly into) the region. This will destabilize the atmosphere. The region may also see a surge of moisture from Hurricane Lorena, which is presently in the Eastern Pacific Ocean and will be moving into Mexico and West Texas this weekend. All of that to say, we will perhaps see rain chances in the vicinity of 40 percent on Saturday, and 60 percent or higher on Sunday. Something to monitor if you have plans this weekend.

Next week

Our weather next week will depend on whether the region sees any impacts from the aforementioned front. Generally I would expect highs in the vicinity of 90 degrees, with some lingering rain chances to start the week followed by a drier pattern. We’ll see!

Atlantic Tropics

There’s a rather ominous looking red blob at the moment in the National Hurricane Center’s seven-day tropical outlook. At this point there is no clear guidance on where this storm will go, or how strong it will get. My general sense is that the odds of something making it into the Gulf from this system are fairly low, however. Head over to The Eyewall for all of the gory details.

In brief: Today’s post reviews the summer of 2025 in Houston. Some residents may believe this one felt cooler than is typical. We see what the data says about that. Additionally, we look ahead to this week’s weather in the wake of a front that finally pushed through over the weekend.

A review of summer 2025

August has come to an end. For most of us, in terms of weather at least, that is cause for celebration. Not because the kids are back in school, and teachers back at work. Not because summer vacation is over. But rather, because August is the hottest and most severe month for weather in Houston, and cooler conditions are on the horizon. September 1 also marks the start of meteorological fall, so it allows us to step back and ask, how hot was this summer?

My immediate reaction is that this summer felt fairly mild. There were no prolonged periods of high pressure and blazingly hot days. However, when we dig a little deeper, we find a different answer. Matt already wrote about this in one of our monthly Q&A’s, but this summer has been sneakily hot. When we look at the “average” temperature for June, July, and August of this year, we get a value of 86.0 degrees. This is simply the daily high, and daily low, divided by two for the last three months. It turns out this summer was the sixth hottest June, July, and August in nearly 150 years of Houston temperature records.

You might say, well, it did not feel that hot. And you’re right, the days were not blistering hot. In terms of daily highs, our average of 94.9 degrees only ranked 12th on record in Houston. My sense is that summer days felt cooler because a) we had more clouds and periodic rainfall to help cool days off, and b) recent summers such as 2022 and 2023 were so incredibly hot that they have reset our expectations of normal. Where this summer was exceptionally hot, however, was at night, when the daily minimum temperature averaged 77.0 degrees. This is tied for second, all time, behind only 2023 (77.4 degrees).

So what’s going on here? Well, it’s complicated. Certainly the urban heat island effect (widespread sprawl and concrete, which absorbs more heat) is playing a role. But Galveston and College Station also recorded summers that ranked in the top 10, in terms of overall heat. So there is more happening in the background here. The main driver of our warmer nights is the Gulf, which greatly influences our nighttime temperatures. This is due in no small part to warmer oceanic temperatures around the planet. Our world is heating up, and in Houston we are experiencing that even during a “mild” summer.

Tuesday

Following widespread rainfall over the holiday weekend, showers this morning are mostly offshore after a weak front has moved into the area. I think we’ll still see a slight chance of rain later this morning (30 percent, maybe) for areas along and south of Interstate 10, but the trend is clear. We are going to see an influx of moderately drier air over the next couple of days. Skies today should be mostly sunny, with high temperatures in the vicinity of 90 degrees. Low temperatures tonight will drop into the mid-70s in the city, with slightly cooler temperatures possible for inland areas.

Wednesday, Thursday, and Friday

These will be the driest days, which in early September means there still will be some humidity. Still, it should feel a little bit drier outside, with highs likely reaching the lower 90s in Houston, and mid-90s for some inland areas. Skies will be sunny, with virtually no chance of rain. I think Wednesday night into Thursday morning will see the “coolest” weather, with some inland locations potentially hitting the upper 60s. Obviously this is not cold, but the nights and mornings should feel a little bit more mild.

Saturday, Sunday, and beyond

Some time on Friday, probably, the pattern will change as the onshore flow returns. This will raise humidity levels and should give us a warmer night on Friday, and start to increase rain chances this weekend. At the same time another front will approach our area from the north. It is not entirely clear whether this front will push down into Houston and off the coast, or stall. But the bottom line is that we probably will go from highs in the low 90s on Saturday to the upper 80s on Sunday and Monday, with a decent chance (maybe 30 percent) of showers on Saturday and better chances on Sunday into early next week. I don’t think we’ll see a repeat of the heavy rains we experienced over Labor Day weekend, but I cannot be sure of that. Most of next week should see highs in the vicinity of 90 degrees.

In brief: Another smattering of downpours is likely today, however, it will probably favor the southern fringe of Houston (Galveston/Brazoria Counties). Much calmer weather begins tomorrow, along with less humid weather thanks to our cold front as well. It still looks hot, but it will be much more tolerable at times, especially in the mornings.

Yesterday saw some impressive rains resulting in some street flooding and a flash flood warning near and just southeast of downtown Houston. Rain totals over 3 inches are plotted below.

We had just shy of 6 inches near 45 and the South Loop, just shy of 5 inches at Hirsch and Tidwell, and over 3 inches on the University of Houston campus. Overall, it was quite an active afternoon.

As for today, we’ll probably take down the Stage 1 flood alert we put in yesterday by this evening. There will still be downpours around today, and I think areas south of I-10, particularly down near Galveston or in Brazoria County will have the highest odds of some localized street flooding. Just a heads up for anyone returning from the coast from the holiday weekend.

Otherwise, look for intervals of sun and clouds with highs generally in the upper-80s to low-90s.

Rest of this week

A rather tranquil early September week awaits Houston. In terms of thunderstorms, other than an isolated one tomorrow, it looks like our next real chance at showers will wait til the weekend. Our first “front” of autumn is here now, and this about as good as we can hope for in the first week of September. We will actually see daytime highs increase this week, owing to a combination of fewer storms and drier air. In fact, by Thursday or Friday, we could be pushing the upper-90s again. But that drier air means it will be less humid than usual for the first week of September.

Less humid air should also translate into mornings that feel half-decent; not cool by any means but quite tolerable. A few locations on the outskirts of the metro area should see lows in the 60s I would imagine by Wednesday or Thursday morning. Overall, I’m not sure you could realistically script a much nicer week to open September with!

Another cool front is going to try and approach again later this week. This one will have limited luck in pushing through, but this could again reinforce the somewhat drier air mass over Texas early next week as well.

Tropics

The tropics continue to look calm in the Gulf. There is one area with (at least) a 40 percent development chance in the Atlantic, but this one will take a few days to get moving and is over a week out from the islands, not a concern for the Gulf at this point.

We have about 4 to 5 weeks of peak Texas hurricane season remaining. The first one looks good. Fingers crossed.