Allergy Calendar for April 2026 in Europe: When Pollen Will Peak, Where It Will Be Worst, and How to Get Through the Season

📋 Key points at a glance

April 2026 in Europe is a month dominated by tree pollen. The main allergen is birch, with the highest burden expected in the United Kingdom, Germany, Poland, the Czech Republic, Austria, Belgium, the Netherlands, the Baltic states, southern Scandinavia, and parts of Central Europe. Alder, hazel, ash, and locally willow also remain relevant early in the month. The highest risk is expected on dry, warm, sunny, and windy days. Rain can bring short-term relief, but after a sharp warm-up pollen levels often rise quickly again. Across Europe, the toughest periods are most likely in Central, Northern, and Northeastern countries, where spring pollen loads are usually the most intense.

April is one of the hardest months of the year for people with seasonal allergies across Europe. According to European SILAM/CAMS model guidance, operational pollen maps, and Met Office forecasts, birch pollen concentrations are especially high at the start of the month, with levels already reaching high and very high in several countries. That is why queries such as what can cause allergies in April rise sharply every spring. In most cases, the main triggers are trees — especially birch, ash, alder, and in some places willow — while grasses begin to strengthen toward the end of the month in southern Europe. For Pogodnik readers, this matters because spring pollinosis in Europe often coincides with unstable weather, wind, dry air, urban dust, and sharp temperature swings, so daily monitoring of weather conditions and pollen levels can help reduce the burden on the body and make it easier to adjust routines in advance.

What blooms in Europe in April

The first half of April 2026 in Europe is shaped mainly by tree pollen. The most important contributors are birch and ash. In cooler areas, alder and hazel still linger, while in river valleys, damp parks, and suburban green zones willow allergy can also become relevant. Although willow rarely acts as the sole cause of severe symptoms, in sensitive people it can intensify the overall pollen burden, especially when several tree species are flowering at the same time.

This is particularly important across Central and Northern Europe, where pollen pressure can build unevenly from one country to another and even from one city to the next. In the United Kingdom, Germany, Poland, the Czech Republic, Austria, and the Baltic region, urban areas can experience a faster increase in exposure during dry spells, while suburban and park-heavy areas may remain more problematic because of nearby pollen sources. In the second half of the month, birch remains active, but the geography of the peak gradually shifts northward and eastward. In Central Europe and southern Scandinavia, this is often the most difficult stretch of the spring season. In southern Europe, grass pollen begins to join the tree pollen background, and by late April local Mediterranean allergens also become more important.

Allergy calendar for April 2026: where and when the risk is highest

📅 April 1–5

Where it is worse: southern and central England, Wales, Belgium, the Netherlands, western and central Germany, Poland, the Czech Republic, Austria, Slovenia, and parts of northeastern France

Main allergens: birch ash residual alder willow

At the start of the month, the heaviest pollen load is expected across a belt stretching from northeastern France and the Benelux countries through Germany, Denmark, Poland, the Czech Republic, and Austria. In the United Kingdom, Met Office guidance already shows Very high birch levels in many parts of England and Wales. In Central Europe, symptoms are likely to intensify on dry, breezy days, especially in cities and districts with a large amount of birch, alder, and willow. In Slovenia, dry and warm weather also helps release and transport pollen more efficiently.

📅 April 6–10 — the first serious peak

Where the risk is highest: England, Wales, northern France, Belgium, the Netherlands, Germany, Poland, Denmark, the Czech Republic, and neighboring parts of Central Europe

Allergens: birch ash polyvalent allergy

This is one of the most difficult periods of the first half of the month. According to Met Office data, birch pollen concentrations stay at a Very high level for several consecutive days across many parts of England and Wales. If you already tend to flare up in spring, this interval should be treated as the first major April peak. Elsewhere in Europe, people sensitive to tree pollen may also feel worse during this period, especially where several species are flowering at once and the weather remains dry. It is often hardest for people with polyvalent allergy, where the reaction is driven by multiple allergens at the same time.

📅 April 11–15

Where a peak is likely: Germany, Poland, the Baltic states, southern Sweden, southern Finland, Denmark, and parts of northeastern Europe

Allergens: birch

After shifts in air masses and scattered rainfall, short windows of relief are possible, but the season does not end. In Central European countries, birch pollen remains the leading trigger. Farther north, the season is only gaining momentum. Across Europe, many allergy sufferers are likely to notice a wave-like pattern during this period: conditions ease slightly after rain, then worsen again once sunshine, warmth, and wind return.

📅 April 16–20

Where it is worse: Poland, Lithuania, Latvia, Estonia, southern Sweden, southern Norway, southern Finland, while Central Europe still remains under pressure in dry spells

What is added: first grasses in southern France, northern Italy, the Balkans, and Iberia

The zone of maximum pressure increasingly shifts toward northeastern Europe. At the same time, Central Europe still keeps a High background on warm, dry days, especially when sunshine and wind return quickly after rain. For much of Europe, this is still a period when birch remains highly significant, while the overall burden can also be amplified by dust, dry air, and more intensive ventilation of homes and vehicles.

📅 April 21–25 — the main peak for the northeast

Countries with a high probability of severe days: Finland, Sweden, Estonia, Latvia, Lithuania, northern Poland, and locally other northeastern parts of Europe

Allergens: birch birch + grasses in the south

In Scandinavia and the Baltic states, warm and windy weather can cause birch pollen concentrations to rise sharply. In Central Europe, levels range from Moderate to High depending on rainfall and the daily weather cycle. By late April, some people across Europe may still experience pronounced symptoms, especially if they are sensitive not only to birch but to several spring allergens at once.

📅 April 26–30

Where: northern Europe — birch; southern Europe — grasses and olive

Allergens: birch grasses olive

Birch remains an important allergen in the north, but in southern Europe the grass season becomes increasingly visible. Around the Mediterranean, olive and other local allergens gradually gain importance. Ragweed is not yet the main factor in April — its classic season comes in late summer and early autumn — but for allergy sufferers with polysensitization it is already worth keeping future cross-reactions in mind. In parts of Europe, the end of April does not necessarily mean full relief: on dry and windy days, symptoms can return even as the overall tree pollen background slowly declines.

Where the risk is highest in Europe in April 2026

🇬🇧 United Kingdom

Very high Birch, especially in England and Wales. Peak: April 1–15.

🇩🇪 Germany

High Birch + ash across much of the country. Peak: April 1–20.

🇵🇱 Poland

High Birch. The peak is stretched across most of April.

🇧🇪 Belgium / 🇳🇱 Netherlands

High Birch. The risk is elevated in the first half of April.

🇨🇿 Czech Republic / 🇦🇹 Austria

High Birch + ash. Peak: April 1–15.

🇪🇪 Estonia / 🇱🇻 Latvia / 🇱🇹 Lithuania

High Birch. Peak: April 16–25.

🇫🇮 Finland / 🇸🇪 Sweden

Moderate → High Peak: late April.

🇪🇸 Spain / 🇮🇹 Italy / 🇫🇷 France (south)

Grasses Olive Mixed season by late April.

How weather affects allergies in April

Weather	Impact on allergy sufferers
☀️ Dry + warm + windy	The worst combination. Pollen is released easily and can travel for dozens of kilometres. Symptoms are usually at their strongest. This is especially relevant across Europe during windy spells and rapid daytime warming.
🌧️ Rain	Temporarily clears the air. Relief may last for several hours. But after a sharp warm-up, a new pollen wave often returns within 12–24 hours.
🌫️ Cloudy + cool	Usually slows the season. But in some patients damp conditions increase irritation of the mucous membranes and raise the burden from mould.
🌊 Wind without rain	Dangerous: it carries allergens far from the source of flowering. In Europe, this often worsens symptoms even in people who are not close to the trees themselves.
🌞 Sudden warm-up	Speeds up flowering. After a cold week, it can trigger an abrupt spike in pollen concentration.

Cross-reactive allergens in April

🍅 Birch (the main April scenario): with birch pollen sensitivity, reactions often appear to raw apples, pears, peaches, apricots, plums, cherries, carrots, celery, hazelnuts, almonds, and sometimes soy. This is known as pollen-food syndrome or oral allergy syndrome. Many people think a new food allergy has suddenly started, but in reality the problem often begins with pollinosis.

💕 How food allergy appears on the background of pollinosis: it is usually itching or tingling in the mouth, throat irritation, mild lip swelling, and more rarely hives or a more pronounced reaction. If symptoms go beyond the mouth and throat area, an in-person consultation with an allergist is needed.

🌿 Grasses (southern Europe, late April): cross-reactions with tomato, celery, orange, melon, and peach.

🍔 Ragweed (relevant later): the classic cross-reactive foods are banana, cucumber, melon, and courgette. This is especially worth remembering in advance in Europe because ragweed becomes one of the most aggressive allergens in late summer and early autumn in some regions.

What else can cause allergies in April besides pollen

Although April is mostly associated with pollinosis, not every rash or runny nose is caused by trees. The list is wider:

House dust mites — a year-round trigger that worsens in humid conditions
Mould — especially active indoors after a damp winter
Animal dander, household chemicals, food triggers
Mosquito bites — in warmer regions, early episodes are possible already in spring; this is usually a large local swelling, redness, and itching
Cold urticaria — itchy wheals and redness after contact with cold air or water; in spring it is sometimes mistaken for an “unusual pollinosis”
Alcohol — not a separate allergen, but it can intensify existing allergic rhinitis because of vascular reactions and the histamine content of some drinks

Main pollinosis symptoms in April

👅 Frequent sneezing and itching in the nose

👔 Watery runny nose or congestion

👀 Redness and tearing of the eyes

🗣 Itching of the palate, throat, and ears

🤑 Cough, irritation, postnasal drip

🧐 Reduced concentration, fatigue, headache

🦝 Asthma worsening in sensitive patients

💤 General tiredness even without other symptoms

Tips for allergy sufferers in April 2026

🎶 Plan walks after rain or in the evening — locally, pollen concentrations may be lower at those times.

🏠 Keep windows closed during the windiest and driest hours, especially in the morning and during the day.

🛀 After being outdoors — change clothes, wash your face, and wash your hair before bed so you do not carry pollen onto your pillow.

👓 Use glasses outdoors and cabin filters in the car. Dry laundry indoors.

💊 Antihistamines and nasal steroids — take them preventively according to the plan, not only after a very bad day begins. If eye symptoms are pronounced, separate eye drops may also be needed.

🩺 If every April is hard for you — discuss allergy testing and the possibility of allergen immunotherapy before the next season.

📱 To avoid missing dangerous days, it helps to track weather, wind, and the overall background in the Pogodnik app: across Europe, this is especially useful in spring, when dry and windy weather can quickly intensify allergy symptoms.

When urgent help is needed

🚨 Call a doctor immediately if the following appear against the background of allergy:

• wheezing and increasing shortness of breath
• marked swelling of the lips, tongue, or throat
• generalized hives
• weakness, dizziness, or a sudden drop in blood pressure

This is no longer ordinary pollinosis. Delaying is dangerous.

April summary

April 2026 in Europe is a month of high burden for people with tree allergies. The main allergen remains birch, while alder, ash, and locally willow often add to the overall spring load. At the beginning of the month, the greatest risk is focused on Central Europe and parts of Western Europe, while by the middle and end of April the zone of highest pressure gradually shifts toward the north and northeast of the continent. If spring is hard for you, this is exactly the time to monitor pollen forecasts every day and adapt your routine accordingly. For Pogodnik readers, the main conclusion is simple: the combination of dry, warm, and windy weather almost always worsens symptoms, which means prevention and early response matter more than trying to cope only once the flare is already at its peak.

📚 Sources: SILAM / Finnish Meteorological Institute, CAMS / Copernicus Atmosphere Monitoring Service, Met Office, NHS, AAAAI, ACAAI. This material has been adapted for the Pogodnik audience for informational purposes and does not replace an in-person medical consultation.

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