Warm Weather Brings Early Spring Allergies & Butterfly Sightings in Netherlands

February 28, 2026 David Kessler - News Editor News

Early Spring Pollen Surge: Warm Weather Triggers Hay Fever Symptoms

The unseasonably warm weather currently blanketing much of the Netherlands is prompting an early start to hay fever season, with rising pollen counts already causing discomfort for allergy sufferers. While the true arrival of spring is still weeks away, temperatures reaching as high as 22°C are stimulating plant growth and pollen release, particularly from hazel and alder trees. This unexpected surge in pollen levels is causing concern for those prone to allergic rhinitis, commonly known as hay fever.

A Premature Pollen Season

Reports indicate that the mild temperatures are accelerating the development of trees and shrubs, leading to a significant release of pollen into the air. According to Pollennieuws.nl, hazel and alder pollen are currently being released in substantial quantities, especially in areas experiencing drier conditions. These pollens are considered moderately allergenic, affecting approximately 700,000 people in the Netherlands. While rainfall can temporarily clear the air, prolonged dry spells and windy conditions exacerbate the problem, allowing pollen to travel and spread more easily. You can find more information about pollen forecasts at Hooikoortsradar.

What the Radar Shows: Current Pollen Levels

The daily pollen radar, as reported by Allesoverallergie.nl, currently indicates “no to some” levels of pollen from trees, grasses, and weeds across the country. Specifically, birch, alder, hazel, oak, and cedar trees are releasing pollen. While grass and weed pollen levels remain low for now, the early bloom of trees is already causing issues for sensitive individuals. The radar provides a useful tool for those wanting to monitor pollen levels in their specific location, helping them to prepare and take necessary precautions. You can check the daily pollen radar here: Allesoverallergie.nl.

Code Orange: High Pollen Risk

Hooikoortsalert.nl currently issues a “code orange” alert for the Netherlands, signifying a heightened risk for hay fever sufferers. The alert notes the 22°C temperature, limited rainfall, and moderate wind, all contributing to increased pollen dispersal. While the lack of rain is generally positive, it also means pollen isn’t being washed away, increasing its concentration in the air. This combination of factors creates a challenging environment for those with pollen allergies. More details on the current alert can be found at Hooikoortsalert.nl.

Understanding Hay Fever and its Symptoms

Hay fever, or allergic rhinitis, is an allergic reaction to pollen. Symptoms can mimic those of a cold or flu, including sneezing, a runny or blocked nose, itchy eyes, and a sore throat. However, unlike a cold, hay fever is not caused by a virus and is not contagious. The Nivel institute collects weekly data on health problems reported to doctors, and their data shows a clear distinction between hay fever and influenza-like illnesses.

The Rise in Doctor Visits

Data collected by the Nivel institute shows a pattern in doctor visits related to allergic rhinitis. While numbers are typically low during the winter months, they commence to rise in February, indicating the start of the hay fever season. The institute’s data, collected anonymously from electronic medical records, provides valuable insight into the prevalence of hay fever and its impact on public health.

Beyond Hazel and Alder: What’s Next?

Currently, hazel and alder are the primary culprits for hay fever symptoms. However, as temperatures continue to rise and the season progresses, other trees, grasses, and weeds will begin to release pollen, extending the duration of the allergy season. The timing of peak pollen release for each plant type varies depending on weather conditions and geographical location. It’s important to stay informed about the pollen forecast and take appropriate measures to manage symptoms throughout the spring and summer months. A recent report in RTV Utrecht highlighted the early impact of alder and hazel pollen, noting the increase in reported symptoms. You can read more about this here: RTV Utrecht.

Managing Your Hay Fever

For those susceptible to hay fever, several strategies can help manage symptoms:

  • Monitor pollen counts: Stay informed about the daily pollen forecast in your area.
  • Limit outdoor exposure: On high pollen days, try to stay indoors as much as possible.
  • Keep windows closed: Keep windows and doors closed to prevent pollen from entering your home.
  • Leverage air purifiers: Consider using an air purifier with a HEPA filter to remove pollen from the air.
  • Take medication: Over-the-counter antihistamines, nasal sprays, and eye drops can help relieve symptoms. Consult with a doctor or pharmacist for advice on the best treatment options for you.
  • Shower and change clothes: After spending time outdoors, shower and change clothes to remove pollen from your skin and hair.

The early onset of hay fever symptoms this year serves as a reminder to prepare for a potentially challenging allergy season. By staying informed and taking proactive steps, individuals can minimize their exposure to pollen and manage their symptoms effectively.