How Weather Affects Sourdough

If you’ve ever followed the exact same sourdough recipe twice and ended up with completely different results, you’re not imagining things. One of the biggest variables in sourdough baking isn’t the flour, the starter, or even the recipe itself, it’s the weather.

Sourdough is alive. Your starter contains wild yeast and bacteria that respond constantly to their environment. Unlike commercial yeast, sourdough fermentation isn’t always predictable because it reacts to temperature, humidity, and seasonal changes.

Once you understand how weather changes your dough, baking becomes far less frustrating and much more predictable.

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Warm Weather = Faster Fermentation

During warmer months, sourdough ferments much faster. Higher temperatures speed up yeast activity, which means:

• Your starter peaks sooner

• Bulk fermentation moves faster

• Dough can overproof quickly

• Dough may feel softer or stickier

This is why a dough that usually takes 8 hours to bulk ferment in winter might suddenly be ready in only 3–4 hours during summer.

One thing that helps tremendously during summer baking is monitoring your dough temperature. A simple digital thermometer can completely change how you understand fermentation timing. I personally recommend keeping one in your baking area at all times.

You can find my favorite baking tools here on my Amazon storefront, including thermometers, proofing baskets, and dough containers I use regularly.

During warmer months, sourdough ferments much faster. Higher temperatures speed up yeast activity, which means:

• Your starter peaks sooner

• Bulk fermentation moves faster

• Dough can overproof quickly

• Dough may feel softer or stickier

Common Summer Problems

• Overproofed dough

• Weak structure

• Sticky shaping

• Flat loaves

• Sour flavor developing too quickly

Helpful Summer Adjustments

• Use cooler water

• Reduce starter percentage slightly

• Shorten bulk fermentation

• Watch the dough, not the clock

• Use the fridge earlier if needed

A dough that is rising rapidly, becoming overly puffy, or losing structure is usually telling you it’s ready sooner than expected.

Cold Weather = Slower Fermentation

Cold weather slows fermentation dramatically. Your starter may take twice as long to peak, and dough can seem inactive for hours.

Common Winter Problems

• Dense loaves

• Underproofing

• Weak oven spring

• Starter taking forever to rise

Helpful Winter Adjustments

• Use warmer water

• Extend fermentation times

• Keep dough in a warmer location

• Feed your starter more consistently

• Be patient with bulk fermentation

During winter, many bakers love using proofing baskets and covered dough containers to help maintain structure and temperature stability during fermentation. A reliable Dutch oven also becomes even more important for oven spring during colder months.

I linked the exact style of proofing baskets and baking equipment I use most often in my Amazon baking collection.

Humidity Changes Everything

Humidity affects flour absorption more than most people realize.

On humid days, flour naturally absorbs moisture from the air. This can make dough feel:

• Wetter

• Stickier

• Harder to shape

During dry winter months, dough often feels:

• Stiffer

• Drier

• Easier to handle but sometimes less extensible

One of the best things you can do is avoid adding extra flour too quickly. Give the dough time to absorb water during resting periods before deciding it needs adjustments.

Many bakers also find dough scrapers and Cambro-style containers extremely helpful for handling wetter doughs without overworking them. Those are also linked in my favorite sourdough tools list.

The Biggest Lesson: Stop Watching the Clock

One of the hardest parts of learning sourdough is realizing recipes are guidelines, not strict timelines.

A recipe might say:

• Bulk ferment for 6 hours

• Proof for 2 hours

• Feed starter every 12 hours

But your kitchen may be:

• 68°F in winter

• 80°F in summer

• Extremely humid

• Very dry

That changes everything.

The dough will always tell you more than the timer will.

Signs Your Dough Is Ready

Instead of relying only on time, look for:

• Increased volume

• Smooth surface

• Air bubbles throughout

• Slight jiggle when moved

• Dough feeling airy and alive

These signs matter more than exact fermentation hours.

A bread lame and good scoring knife can also help you see the difference between properly fermented dough and underproofed dough once baked. If you’re building your sourdough toolkit, I’ve linked the ones I personally use in my bread baking favorites.

Final Thoughts

Sourdough teaches patience and observation more than perfection.

Weather changes are not failures, they’re part of baking with a living culture. The more you bake through different seasons, the more intuitive sourdough becomes.

Eventually, you stop asking:“Why didn’t this recipe work?”

And start asking:“What is my dough telling me today?”

That’s when sourdough really starts to click.

About the Baker

Hi, I'm Jenny, the baker behind Bread and More. I run a small microbakery where I bake sourdough breads, bagels, and baked goods for my community.

Here on the blog I share sourdough tips, baking lessons I've learned along the way, and simple guidance to help home bakers feel more confident baking sourdough.