Allergy Calendar for May 2026 in Europe: Pollen Explosion, Worst Days Revealed and Where It Will Hit Hardest

May is one of the most dangerous months for allergy sufferers across Europe. According to SILAM pollen models and the Met Office forecast trends, this is when the pollen season shifts from trees to grasses — and symptoms often become more intense and widespread. In recent years, the pollen season has become longer and stronger due to climate change, increasing exposure across the continent.

What Causes Allergies in May in Europe

If you’re wondering what causes allergies in May, the main triggers are:

• Grass pollen (dominant allergen)
• Oak pollen (early May)
• Birch (lingering in Northern Europe)
• Plane trees (urban areas)
• Olive pollen (Southern Europe)

According to Met Office seasonal data, the grass pollen season typically begins in May and continues into summer, becoming the most widespread allergen across Europe.

When Pollen Will Peak in May 2026

May 1–7

Early May still carries residual tree pollen, especially oak and birch in northern regions. Grass pollen begins rising in Western and Southern Europe.

Highest risk: UK, France, Germany, Netherlands, Northern Italy

May 8–14 (FIRST PEAK)

This is the first major pollen wave. Warm, sunny, and dry weather allows grasses to release large amounts of pollen. According to meteorological analysis, these conditions significantly increase airborne pollen concentrations.

Worst-hit regions: UK, Ireland, France, Germany, Belgium, Poland

May 15–19

Temporary fluctuations depending on rainfall. Showers may briefly reduce pollen levels, but concentrations quickly rebound after warming.

May 20–28 (SECOND & STRONGEST PEAK)

The most intense pollen period of the month. Grass pollen dominates across nearly all of Europe.

Critical zones:

• Central Europe (Germany, Poland, Czech Republic)
• Western Europe (France, Benelux)
• Northern Europe (UK, Denmark, Southern Scandinavia)

May 29–31

High pollen levels continue, especially in dry continental regions.

Where It Will Be Worst in Europe

Based on SILAM dispersion modeling and European pollen maps, the highest pollen concentrations in May 2026 are expected in:

• United Kingdom
• France
• Germany
• Poland
• Belgium Netherlands
• Denmark
• Southern Scandinavia

SILAM models simulate how pollen spreads across Europe using atmospheric transport data, helping identify cross-border exposure risks.

How Weather Will Affect Allergies

Weather plays a crucial role in pollen intensity:

• Warm + dry + sunny: maximum pollen release
• Wind: spreads pollen over long distances
• Rain: temporarily reduces pollen

Met Office reports confirm that warm, dry, and breezy conditions create ideal environments for pollen release and dispersion.

Symptoms: How Pollen Allergy Manifests

If you’re unsure how pollen allergy manifests, typical symptoms include:

• Sneezing and runny nose
• Itchy, red, watery eyes
• Nasal congestion
• Cough and throat irritation
• Fatigue and headaches

Symptoms usually appear when pollen levels exceed certain thresholds in the air.

Cross-Reactions and Food Allergies

Grass pollen can trigger cross-reactions with:

• Tomatoes
• Melon
• Peaches
• Citrus fruits

This is why many people notice symptoms similar to food allergies during pollen season.

Expert Tips: How to Survive May Allergy Season

• Avoid outdoor activity during peak hours (morning afternoon)
• Keep windows closed during high pollen days
• Shower and change clothes after being outside
• Use sunglasses to protect eyes
• Start antihistamines before symptoms worsen

Final Outlook for May 2026

May 2026 will be dominated by grass pollen across Europe, with two major peak periods likely. Due to warmer and drier conditions, pollen levels are expected to remain high or very high for extended periods. Climate trends continue to intensify allergy seasons, making real-time monitoring essential for managing symptoms effectively.