July Pollen Frontline 2025 - Grasses Take Center Stage! A Complete Guide to Understanding and Overcoming "Summer Hay Fever"

July Pollen Frontline 2025 - Grasses Take Center Stage! A Complete Guide to Understanding and Overcoming "Summer Hay Fever"

2025年07月02日 16:45

1. Main Pollen Flying in July

1-1 Poaceae (Cocksfoot, Timothy, etc.)

  • In the Kanto region, dispersal begins in mid-April, with the actual peak lasting until early July. In Hokkaido, the peak is throughout June, with a decreasing trend in July. In Kyushu, the peak is slightly earlier, so July is a "downhill" period, though there may be days with high concentrations locally.brand.taisho.co.jp

  • While the particles are large and do not travel far, the grass height is lower than eye level, making running and leisure on lawns risk factors.


1-2 Autumn Weed Pollen Appearing Early

  • Ragweed usually appears from late August, while Mugwort and Humulus are mainly in September. However, due to global warming, in urban areas of western Japan, there are years when measurements increase from late July.weathernews.jp



2. Characteristics of Symptoms and Differences from Spring

ItemSpring (Cedar & Cypress)Summer (Mainly Poaceae)
Eye Itching & Redness△◎ Strong brand.taisho.co.jp
Skin Itching△○
Sneezing & Runny Nose◎◎
Cough & Asthma-like Symptoms△△〜○

Point: Poaceae symptoms are more pronounced in the eyes. The use of antihistamine eye drops and sunglasses is more important than in spring.



3. 2025 Dispersal Trends and Predictions

  • According to official observations in Tokyo, the total dispersal of cedar and cypress pollen settled at 70% of the previous year, while Poaceae remained at usual levels.resemom.jp

  • The Japan Weather Association warned in May to "be cautious of Poaceae even after cedar and cypress season ends." If the lack of rain in June continues, dispersal is expected to increase in early July.tenki.jptenki.jp



4. Why Hay Fever is More Likely in Summer

  1. Delayed Weed Cutting: Mowing of vacant lots and riverbanks in urban areas is postponed until after the rainy season, leaving dispersal sources.

  2. Increased Outdoor Activities: Long stays on grass during club activities, festivals, and camping.

  3. High Temperature and Humidity Sensitize Mucous Membranes: Sweat and sebum adhere around the eyes and nose, reducing barrier function.



5. Symptom Check and Diagnosis Flow

  • Timing: Same symptoms every year around the end of the rainy season → High possibility of Poaceae.

  • Definitive Diagnosis: Serum-specific IgE test, prick test. Multiple pollen co-occurrence is common.

  • Self-diagnosis Not Recommended: Cases of worsening bronchial asthma exist.



6. Measures—Daily Life, OTC Drugs, Medical Care

  1. Behavioral Therapy

    • Avoid tall grass and vacant lots.

    • Remove pollen immediately with a shower after returning home.

  2. Self-care

    • Second-generation antihistamines + artificial tear eye drops.

    • Use sunscreen + barrier cream to protect the skin.

  3. Medical Institutions

    • Short-term intensive control with steroid nasal and eye drops.

    • Sublingual immunotherapy is less common than for cedar and dust mites but is conducted at some facilities.



7. Cross-reactions and Food Allergies

Some Poaceae pollen allergy patients develop oral allergy syndrome with melon, tomato, peanuts, etc. Any first-time discomfort should be checked by a doctor. env.go.jp



8. Organize with Q&A! Common Questions

Q1. Do symptoms ease immediately after the rainy season ends?
A. Dispersal temporarily decreases with rain, but increases again with continued sunny and hot weather.

Q2. Is wearing a mask enough before mowing?
A. Due to the large particle size, focus on fit. N95 equivalent is effective.



9. Summary

The notion that "summer = pollen-free" is a misconception. In 2025, Poaceae dispersal is expected to be at usual levels, and in some regions, the prelude to autumn pollen has already begun.Focus on eye symptom measures and quick care after outdoor activities to enjoy a comfortable summer vacation!


List of Reference Articles

  • Taisho AllerLab "Hay Fever Even in Summer? Pollen Flying Outside of Spring" (Update Date Not Listed)

  • Taisho AllerLab "Symptoms and Measures for Poaceae Pollen Allergy" (2024)

  • Japan Weather Association tenki.jp "Caution for Poaceae Even After Cedar and Cypress Season Ends" (2025/05/07)

  • Ministry of the Environment "Pollen Allergy Environmental Health Manual Chapter 2" (2014)

  • Weather News "Pollen Calendar 2025" (2025 Edition)

  • Tokyo Metropolitan Health and Welfare Bureau "2025 Spring Pollen Dispersal Observation Results Report" (2025/05/27)

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