Houston Heatwave: Is Sunscreen Toxic Without Shade?

By Franklin Everett Shaw

December 28, 2025

It’s not just hot in Houston; it’s a different kind of hot. It’s the kind of heat that makes you question your life choices as you walk from your air-conditioned car to the air-conditioned grocery store. And if you’re brave enough to venture outside for longer than five minutes, you’re battling not just the sun, but also the humidity that clings to you like a second skin.

Navigating Houston’s summer heat requires a strategy, especially when it comes to sun protection. Forget the generic sunscreen advice; we need a Houston-specific survival guide.

Let’s dive into the sticky situation of sunscreen in the Bayou City.

The big question: chemical vs. physical sunscreen. Chemical sunscreens absorb UV rays, converting them into heat that’s released from the skin. Physical sunscreens, like zinc oxide and titanium dioxide, create a barrier that reflects UV rays.

Here’s the Houston twist: In intense, prolonged sun exposure with limited shade – think a day at Discovery Green or a sweaty afternoon at a Dynamo game – the heat generated by chemical sunscreens could theoretically contribute to overheating, especially for those prone to heat exhaustion.

Now, before you toss all your chemical sunscreens, understand this: the amount of heat generated is minimal. However, in Houston’s already oppressive heat, every little bit counts.

Consider this scenario: You’re volunteering at the Houston Food Bank’s urban garden in the Fifth Ward. Shade is limited, the sun is relentless, and you’re sweating buckets. In this situation, a physical sunscreen might offer a slight advantage by reflecting heat away from your skin, rather than absorbing it.

But here’s the catch: physical sunscreens can be thicker and leave a white cast, especially on darker skin tones. This is where product selection becomes crucial. Look for “sheer” or “micronized” zinc oxide formulas. Brands like EltaMD and La Roche-Posay offer excellent options, though they can be pricier.

SPF is non-negotiable. Houston’s UV index regularly hits extreme levels during the summer. Don’t even think about leaving the house without at least SPF 30. SPF 50 is even better.

Don’t skimp on application. Most people don’t use enough sunscreen. You need about an ounce – a shot glass full – to cover your entire body. Reapply every two hours, or immediately after swimming or sweating.

Speaking of sweating, Houston’s humidity is a sunscreen’s worst enemy. Water-resistant sunscreens are a must, but even those need frequent reapplication. Consider carrying sunscreen wipes for easy reapplication on the go.

Now, let’s talk shade. Finding it in Houston can feel like searching for an oasis in the desert.

• Parks: Hermann Park offers some decent tree cover, but be prepared to compete for it. Memorial Park is vast, but much of it is open and exposed. Check out the Eastern Glades for newer, more intentional shade structures.
• Outdoor Events: Many outdoor events, like concerts at Miller Outdoor Theatre, happen in the evening when the sun is less intense. However, even then, sunscreen is still important.
• Neighborhoods: Older neighborhoods like the Heights and Montrose often have more mature trees that provide better street-level shade.

DIY shade is your friend. Don’t rely solely on what’s available.

• Umbrellas: A large golf umbrella can provide instant shade wherever you go.
• Portable Shade Structures: Consider investing in a pop-up canopy for picnics or outdoor events.
• Strategic Clothing: Wear lightweight, long-sleeved shirts and pants in light colors. Look for clothing with a UPF (Ultraviolet Protection Factor) rating.

Common mistakes Houstonians make:

• Thinking they don’t need sunscreen on cloudy days: UV rays penetrate clouds.
• Applying sunscreen only when they’re going to the pool or beach: Sunscreen should be part of your daily routine, even if you’re just running errands.
• Relying on makeup with SPF: Makeup with SPF is better than nothing, but it’s usually not enough to provide adequate protection. You need a dedicated sunscreen underneath your makeup.
• Forgetting to protect their lips: Use a lip balm with SPF.
• Ignoring the back of their neck and ears: These areas are often overlooked.

Let’s address the concern about chemical sunscreen absorption. Some studies have shown that certain chemicals in sunscreen can be absorbed into the bloodstream. The FDA is still investigating the safety of these chemicals.

While the long-term health effects are still unknown, if you’re concerned, stick to physical sunscreens. They are generally considered safe and effective.

Here’s a practical tip: Before heading out for a long day in the Houston sun, do a “sunscreen test.” Apply your chosen sunscreen to a small area of your skin and see how it feels after a few hours. Does it feel greasy? Does it irritate your skin? Does it hold up to sweat? This will help you find a sunscreen that works for you.

Consider the specific activity. If you’re swimming at the Galveston beach, a water-resistant sunscreen is essential. If you’re attending an outdoor concert at White Oak Music Hall, a lightweight, non-greasy sunscreen is a better choice.

Don’t forget about hydration. Sunscreen is only one part of the equation. Drink plenty of water throughout the day to stay hydrated and prevent heat exhaustion.

Finally, listen to your body. If you start to feel overheated, dizzy, or nauseous, get out of the sun immediately and seek medical attention if necessary. Houston’s heat is no joke.

So, Houstonians, arm yourselves with knowledge, sunscreen, and a healthy dose of common sense. Enjoy the outdoors, but do it safely. And remember, shade is your friend. Seek it out, create it, and embrace it. Your skin (and your sanity) will thank you.