If you suffer from hayfever, the arrival of spring brings a familiar dread. Warmer temperatures, longer days and budding trees all mean one thing: pollen is on the way. Around 13 million people in the UK have hayfever, and for many of them, checking the weather forecast becomes just as much about pollen counts as it is about rain.
This guide covers when each type of pollen peaks in 2026, how the exceptionally wet winter may affect this year's season, and how to use daily weather conditions to manage your symptoms.
When Does Pollen Season Start in the UK?
Pollen season in the UK typically runs from late February through to September, but it is not one continuous event. Three distinct types of pollen dominate at different times of year.
| Pollen Type | Typical Season | Peak Months | % of Hayfever Sufferers Affected |
|---|---|---|---|
| Tree pollen | Late February to June | March to May | 25% |
| Grass pollen | May to August | June to July | 90% |
| Weed pollen | June to September | July to August | 15% |
Grass pollen is by far the most common trigger. If you only get symptoms in midsummer, grass is almost certainly the culprit. If your symptoms start as early as March, tree pollen is likely your trigger.
2026 Pollen Calendar: Month by Month
March
Tree pollen season begins. Hazel and yew are the first to release pollen, followed by ash, birch and oak through the month. Counts are typically low to moderate, but sensitive individuals may notice symptoms on dry, breezy days.
April
Tree pollen peaks. Birch pollen, the most potent tree allergen in the UK, reaches its highest levels. April is often the worst month for tree pollen sufferers. Counts can spike sharply during warm, dry spells.
May
The crossover month. Tree pollen begins to decline while grass pollen starts to rise. Some sufferers experience a brief relief window in early May before grass pollen takes over. Oil seed rape, which covers large areas of the English countryside in bright yellow, also produces pollen that affects some people.
June and July
Peak grass pollen. These are the two worst months for the majority of hayfever sufferers. Counts are highest during warm, dry, sunny weather with gentle breezes. Thunderstorms can cause sudden spikes in symptoms (more on this below).
August and September
Grass pollen fades while weed pollen (including nettle and dock) rises. Fungal spores also increase, affecting people with mould allergies. By late September, the season is effectively over for most sufferers.
How the Wet Winter of 2026 May Affect Pollen
The relentless rain since Christmas raises an obvious question: will 2026 be a good or bad year for hayfever?
The answer is complicated, because a wet winter affects tree pollen and grass pollen in different ways.
Tree Pollen: Possibly a Delayed but Intense Season
Prolonged cold, wet conditions can delay the start of tree pollen season by a week or two. Trees need a sustained period of warmer, drier weather to begin releasing pollen in earnest. If March remains cool and damp, the start of tree pollen season may be pushed back.
However, when the weather does turn, the release can be sudden and intense. A delayed start often means a compressed season with higher peak counts over a shorter period, which can hit sufferers harder than a gradual build-up.
Grass Pollen: Potentially a Big Year
Grass thrives on winter rain followed by spring warmth. The saturated soils and above-average rainfall of early 2026 have created ideal growing conditions. If spring brings reasonable warmth and sunshine, grass growth could be particularly vigorous, leading to higher than average pollen counts from May onwards.
The wet winter of 2013/2014, which was similarly extreme, was followed by a notably intense grass pollen season. While every year is different, the conditions are in place for a repeat.
How Weather Affects Daily Pollen Counts
Understanding the relationship between weather and pollen helps you plan your day. This is where checking your local forecast becomes genuinely useful for hayfever management.
| Weather Condition | Effect on Pollen |
|---|---|
| Warm, dry and sunny | High counts. Pollen is released freely and carried on the breeze |
| Light breeze | Moderate to high. Pollen is dispersed across wider areas |
| Strong wind | Variable. Pollen is spread further but can be diluted |
| Rain | Low counts during rain. Rain washes pollen out of the air |
| After rain (clearing skies) | Counts can spike quickly as trapped pollen is released |
| Cool and overcast | Generally lower counts. Flowers release less pollen in cool conditions |
| Humid, still evenings | Pollen falls to ground level. Symptoms can worsen at dusk |
| Thunderstorms | Danger zone. See below |
Thunderstorm Asthma: A Serious Risk
During thunderstorms, pollen grains can be drawn up into clouds, broken into much smaller fragments by moisture, and then brought back down in concentrated bursts. These tiny fragments penetrate deeper into the lungs than whole pollen grains, triggering severe reactions even in people whose hayfever is usually mild.
This phenomenon, known as thunderstorm asthma, has caused mass casualty events in other countries. In the UK, the risk is highest during June and July when grass pollen counts peak and convective thunderstorms are most common.
If you have hayfever or asthma, stay indoors during summer thunderstorms and keep windows closed.
Regional Differences Across the UK
Pollen counts vary significantly depending on where you are in the country.
Highest Counts
- Central and southern England see the highest grass pollen levels, particularly in rural areas with large expanses of farmland and meadow
- The Midlands often records some of the UK's peak counts due to its inland position and agricultural landscape
- East Anglia experiences high counts in a broad, flat landscape with limited natural barriers
Lower Counts
- Coastal areas benefit from onshore breezes that push pollen inland, making beaches and clifftops some of the best places for hayfever sufferers
- Scotland and Northern Ireland generally have lower and later pollen counts due to cooler temperatures and later growing seasons
- Urban centres tend to have lower grass pollen than rural areas, though tree pollen from parks and gardens can still be significant
The Worst Spots
- River valleys trap pollen in still air, especially on calm evenings
- Near agricultural land during the grass cutting season (late May to July)
- Parks and gardens with silver birch, which is one of the most allergenic trees in the UK and widely planted in urban areas
Practical Tips for Managing Hayfever in 2026
Use Weather Forecasts Strategically
Check your local forecast each morning. If the day is forecast to be warm, dry and breezy, take precautions. If rain is expected, your symptoms are likely to ease during the wet spell, though be prepared for a spike when it clears.
Time Your Outdoor Activities
Pollen counts tend to be highest in the early morning (as flowers open and release pollen) and again in the early evening (as cooling air brings pollen back to ground level). The best time to be outdoors is typically mid-afternoon or during and immediately after rain.
Protect Yourself
- Wrap-around sunglasses reduce the amount of pollen reaching your eyes
- Vaseline around the nostrils traps pollen before you breathe it in
- Shower and change clothes after spending time outdoors
- Keep car windows closed and use the recirculate setting on your air conditioning
- Dry washing indoors during high pollen days; sheets and towels hung outside act as pollen traps
Start Medication Early
Antihistamines work best when taken before symptoms start. If you know your trigger pollen, begin taking medication a week or two before the typical start of that pollen season. For tree pollen sufferers, that means starting in late February or early March. For grass pollen, late April or early May.
Monitor Counts
The Met Office publishes a daily pollen forecast for UK regions. Checking this alongside your weather forecast gives you the information you need to plan your day.
Frequently Asked Questions
When is the worst month for hayfever in the UK?
June is typically the worst month for the majority of hayfever sufferers because grass pollen peaks during this period. For tree pollen sufferers, April is usually the most challenging month, when birch pollen is at its highest.
Does rain help or make hayfever worse?
Rain during a shower washes pollen out of the air and provides temporary relief. However, the period immediately after rain can see a sharp spike in pollen as plants release new pollen into the cleared air. Heavy thunderstorms can make symptoms significantly worse due to pollen grain fragmentation.
Is hayfever getting worse in the UK?
Evidence suggests it is. Climate change is extending the pollen season at both ends; warmer springs mean earlier starts, and warmer autumns mean later finishes. Rising CO2 levels also stimulate plants to produce more pollen. Studies suggest that pollen seasons in the UK are now approximately two weeks longer than they were 30 years ago.
Can you develop hayfever as an adult?
Yes. While hayfever often starts in childhood, it is common to develop it for the first time as an adult. Some people who had hayfever as children find it returns after years of remission. Changes in location, stress levels, and immune function can all trigger adult-onset hayfever.
Does living near the coast help with hayfever?
Generally, yes. Coastal areas tend to have lower pollen counts because onshore breezes blow pollen inland. If you are planning a holiday at the coast, you may find your symptoms improve, particularly at west-facing beaches where prevailing winds come off the sea.
Will the wet winter of 2026 mean less pollen?
Not necessarily. While the wet conditions may delay the start of tree pollen season, they have created ideal conditions for vigorous grass growth, which could lead to a more intense grass pollen season from May onwards. A wet winter followed by a warm, dry spring is historically one of the worst combinations for hayfever sufferers.
