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Grass pollen
Grass (Poaceae: Phleum pratense, Dactylis glomerata, Festuca, Poa and others) is airborne here from june to august, peaking late June to mid-July. Allergenic potency: high. Cross-reacts with tomato, melon, watermelon, orange and others.
This is reference information, not a diagnosis and not a treatment plan. A pollen calendar cannot tell you what you are allergic to, and no page can clear a food as safe for you — only the label on the packet in your hand and the clinician who knows your history can do that. Anything beyond mild, short-lived symptoms in the mouth or nose — swelling that affects breathing or swallowing, hives away from the mouth, wheeze, vomiting or faintness — is an emergency question, not a reading question.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grass | ● | ● | ○ |
● peak weeks · ○ usually airborne. Typical mainland window from the national aerobiology monitoring programmes of the region · checked 2026-09-06
Where it grows here
Grass is the second pillar of the northern allergy year and, unlike birch, it is not one species. Timothy, cocksfoot, meadow fescue, meadow grass and their relatives make up hay meadows, roadside verges, football pitches, lawns and every abandoned field, and they all flower within the same few weeks.
When it is in the air
The season runs from early June to August with the heaviest days between late June and mid-July across the Baltic and southern Finland. Mowing matters: cut lawns and verges produce far less pollen, which is why an unmown meadow in early July is a worse place to sit than a mown park. Rain washes the air clear, and a thunderstorm can briefly make things worse rather than better by breaking grains into smaller fragments.
What it feels like
Grass season produces the heaviest eye symptoms of the year for many people, and it is the season most likely to push allergic asthma. Symptoms load into the late afternoon and evening, when grass pollen concentrations near the ground typically rise, and they are worse after a day spent outdoors.
What it cross-reacts with
Temperate grasses share their major allergens so completely that being allergic to one means being allergic to the group; a test against timothy stands in for all of them. Food cross-reactions exist but are much weaker than birch's — tomato, melon, orange and raw potato are the ones reported, usually as an itchy mouth. Grass pollen allergy is not the same as wheat allergy and is not coeliac disease.
Related pollens: all temperate grasses cross-react with one another almost completely, and with cereal pollen.
Foods reported to cross-react:
TomatoMelonWatermelonOrangePotato (raw)Peanut
A cross-reaction is not the same as a food allergy that started with food, and the difference decides how serious it is. Read how oral allergy syndrome works before drawing conclusions from this list, and note that several of these foods also appear on the fourteen declarable EU allergens for entirely separate reasons.
Named allergen molecules: Phl p 1 and Phl p 5 (the major timothy allergens), Phl p 7 (polcalcin), Phl p 12 (profilin). These are the official WHO/IUIS names, and they are what a component-resolved blood test reports.
What actually helps
Grass is one of the five types in the CAMS European forecast. Practical measures matter more here than in the tree season because the exposure is at ground level and unavoidable outdoors: sunglasses that wrap, hair washed before bed, laundry dried indoors, and someone else cutting the lawn. Grass is also the best-established target for allergen immunotherapy, which is a clinician-led decision.
What gets misread
Grass season is regularly blamed on poplar fluff, which flies at the same time and is visible. It is also blamed on hay itself: hay fever comes from grass pollen in the air in June and July, not from dried hay in a barn in November, which is usually mould.
Sources: Regulation (EU) No 1169/2011, Annex II · Commission Implementing Regulation (EU) No 828/2014 (gluten claims) · WHO/IUIS Allergen Nomenclature · season windows from the national aerobiology monitoring programmes of Estonia, Finland, Sweden, Denmark and Norway · cross-reaction patterns paraphrased from the allergy literature and EAACI material · checked 2026-09-06
Frequently asked questions
When is grass pollen season in the Baltics and Finland?
Grass is airborne from june to august on the mainland, with the heaviest days late June to mid-July. Denmark and southern Sweden run two to three weeks earlier, and northern Finland, Sweden and Norway three to four weeks later.
Which foods cross-react with grass pollen?
The foods reported are tomato, melon, watermelon, orange, potato (raw), peanut. Reactions are usually confined to the mouth and throat and usually disappear when the food is cooked, with exceptions set out on the oral allergy syndrome page.
Is there a live grass pollen forecast?
Yes. Grass is one of the six species the CAMS European model forecasts, so a daily number exists for it through services such as the Open-Meteo pollen API.
How strong an allergen is grass?
High potency, which is a statement about the pollen and not about how much of it is in the air. The two come apart: some of the most abundant particles of the northern summer are among the weakest allergens.
Birch
April to June, high potency.
Oak
May to June, moderate potency.
Pine and spruce
May to June, low potency.
Sorrel and dock
May to August, moderate potency.
Rye and cereals
June to July, high potency.
The whole calendar
All sixteen sources on one twelve-month grid, read forwards and month by month.
Track the season you actually have
A regional calendar is an average. Log symptoms and sleep in TempoLife and the pattern that belongs to you shows up in your own data.