West Norriton Township Mold Forecast
Mold Today
Today (20 September) mold in West Norriton Township is low; alternaria and cladosporium are low.
Mold Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week alternaria and cladosporium will increase.
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Mold Risk
Today - 20 September
| Mold species | Level | Value |
|---|---|---|
| Alternaria | Low | 9/100 |
| Cladosporium | Low | 18/100 |
Tomorrow - 21 September
| Mold species | Level | Value | 7-Day Trend |
|---|---|---|---|
| Alternaria | Low | 5/100 | Steady |
| Cladosporium | Low | 13/100 | Steady |
Local Mold Conditions
This area's annual averages -- about 76% humidity and 13°C -- put overall mold favorability in the elevated range. Overall, this location experiences conditions with humidity remaining high enough across most of the year that indoor moisture control deserves more attention here than in drier areas.
Mold risk peaks from April to June, when average humidity holds around 75% and temperatures sit near 17°C, a combination that favors sustained mold and mildew growth both indoors and outdoors. Rainfall is substantial through this window too -- about 311 mm -- and the resulting dampness on surfaces only adds to how long favorable growing conditions persist. December through February is this area's lower-risk stretch, when cooler, drier air and reduced humidity considerably slow mold growth.
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Frequently Asked Questions About Mold in Pennsylvania
Why do I still have allergy symptoms after the pollen season?
Allergy symptoms after the main pollen season may be caused by mold spores. Outdoor mold levels can remain high into late summer and autumn, when pollen levels are already falling. Mold allergy can cause symptoms similar to pollen allergy, including sneezing, a runny or blocked nose, itchy eyes, coughing, and wheezing.
What are mold spores and why do they cause allergies?
Mold spores are tiny particles released by fungi into the air. When inhaled, they can trigger an allergic reaction in sensitive people. Common symptoms include sneezing, a runny or blocked nose, itchy or watery eyes, coughing, and wheezing.
When are mold spore levels highest?
Outdoor mold spore levels often increase during warm and humid conditions, particularly when there is plenty of decaying vegetation. Levels can vary considerably with weather, season, vegetation, and location, and some types of mold are more common during particular times of the year, e.g. in the Fall.
How can I reduce my exposure to mold spores?
If you are sensitive to mold, check local mold spore levels and forecasts before spending long periods outdoors. On high-risk days, reducing time around dense vegetation, compost, fallen leaves, and other sources of decaying plant material may help limit exposure.
Understanding the Scale
The 0–100 scores represent risk levels, not direct measurements of pollen or air pollutant concentrations. Higher scores indicate higher risk. Pollen and air quality use different thresholds.
Mold
| None | 0 | No or negligible risk of exposure. Pollen/mold exposure is expected to be minimal. |
| Low | 0-25 | Low risk of exposure. Small amounts of pollen or mold spores may be present. |
| Moderate | 25-50 | Moderate risk of exposure. Pollen/mold exposure is expected to be noticeable. |
| High | 50-75 | High risk of exposure. Elevated pollen/mold exposure is expected. |
| Very High | 75-100 | Very high risk of exposure. Pollen/mold exposure is expected to be at or near its highest levels. |
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