Pollen count and allergy info for Toronto

Toronto pollen and allergy report

Last update at (local time)

Today's Pollen Count in Toronto

Pollen types
Tree pollenNone
Grass pollenNone
Weed pollenNone
Source: tomorrow.io

Air quality

Air quality of Toronto today

PM2.5 µg/m³Good
See air quality

Allergy forecast

Toronto pollen count forecast

DayIndex Tree Grass Weed WindWeatherTemperature
Wind rotating 102 degree 6.7 mp/h
Weather icon
68° 53.6°
Sunday, May 19
Wind rotating 152 degree 6.7 mp/h
Weather icon 40%
75.2° 53.6°
Monday, May 20
Wind rotating 175 degree 6.7 mp/h
Weather icon 50%
75.2° 57.2°


How does the pollen count in Toronto compare between different times of the day, such as morning, afternoon and evening?

Understanding the variations in pollen counts throughout different times of the day is essential for those affected by allergies in Toronto. The changes in pollen counts are driven by a variety of factors, including environmental conditions and the behaviour of the plants themselves.

In the morning, specifically between the hours of 5 a.m. and 10 a.m., pollen counts tend to reach their peak. This timing aligns with the natural behaviour of many plants, which release their pollen in the early morning. Additionally, the morning often presents the kind of environmental conditions—cool and humid—that help to keep pollen close to the ground. Dew that forms overnight can also trap pollen, but as the sun rises and temperatures increase, this moisture evaporates, allowing the pollen to become airborne.

As the day progresses, the pollen count usually starts to decline. This decline is most noticeable from late morning through to the afternoon. During this period, higher temperatures and stronger sunlight can cause some types of pollen to break down, reducing their count. At the same time, increased human activities such as traffic and construction can stir up dust and other particulates, which may help to disperse pollen away from concentration areas.

Into the late afternoon and evening, the count continues to drop. Temperatures usually decrease, and in the absence of wind, pollen begins to settle. Some plants also close their flowers in the evening, halting pollen release. This makes the evening hours a generally safer time for those who are sensitive to pollen to engage in outdoor activities.

However, it's crucial to consider the role of wind in pollen dispersal. A windy day can lead to an increase in pollen counts at any time, overriding the general pattern. Wind can carry pollen from other areas and even stir up pollen that has settled, leading to elevated counts that can affect sensitive individuals unpredictably. Therefore, it's always a good idea to check the current local pollen count and wind conditions before planning your day if you're sensitive to pollen.

This understanding of how pollen counts change throughout the day in Toronto can offer valuable insights for residents, especially those who have pollen allergies or respiratory issues. It allows for better planning of outdoor activities and provides a basis for more effective management of symptoms.

What are the seasonal differences for the pollen count in Toronto?

Toronto experiences distinct shifts in pollen count throughout the year, primarily influenced by the cycles of different plant species. Let's break down these changes by season to offer a more nuanced understanding.


Spring is a season of high activity for tree pollen. In Toronto, the types of trees that contribute most significantly to pollen count include oak, maple, and birch. From late March to May, these trees release pollen into the air, causing spikes in pollen levels. Pollen counts can be particularly high on dry and windy days. This is the time of year when individuals who are sensitive to tree pollen may experience allergy symptoms, including sneezing, itchy eyes, and nasal congestion.


As spring transitions into summer, a shift occurs in the types of pollen in the air. During this season, grasses become the primary contributors to pollen count. Grasses such as ryegrass and Kentucky bluegrass are common in Toronto and the surrounding regions. Unlike tree pollen, which peaks in the morning, grass pollen levels tend to be more consistent throughout the day. Therefore, people who are sensitive to grass pollen may experience discomfort throughout the daylight hours.


During autumn, the focus shifts again, this time to weed pollen. Among the weeds, ragweed is the primary contributor to the pollen count. Ragweed is a resilient plant that thrives in a variety of environments, from fields to roadside ditches. The pollination period for ragweed usually starts in late August and continues until the first frost, usually in October. Even though ragweed pollen grains are lightweight and can travel great distances on the wind, their impact on air quality and human health is not to be understated. Individuals with a sensitivity to weed pollen might experience worsening symptoms during this season.


Winter is a season of respite when it comes to pollen counts in Toronto. During the colder months, most plants are dormant, which means that pollen counts are generally low. However, indoor pollen can be an issue for some people, especially when houseplants are involved. Even though the pollen count is low outdoors, some may still experience allergies triggered by indoor sources.

Overlapping Seasons

It's worth noting that some periods of the year are particularly challenging due to overlapping pollen sources. Late spring to early summer is often cited as the most burdensome period for those suffering from allergies, as this is when tree and grass pollens often coincide. During these months, pollen counts can reach their yearly peak, especially on dry, warm, and windy days.

By understanding these seasonal differences in pollen counts, Toronto residents and visitors can take appropriate measures to manage their symptoms more effectively.

How does the weather affect the pollen count in Toronto?

Weather conditions have a direct impact on pollen counts in Toronto, with various elements such as wind, rain, and temperature playing distinct roles.


Wind is one of the most critical factors that affect pollen dispersal. On windy days, pollen from trees, grasses, and weeds can spread over large distances. This results in elevated pollen counts and can be particularly challenging for individuals who are sensitive to pollen.

Even on days with moderate winds, pollen levels can rise significantly due to the ability of the wind to carry pollen from various sources. However, it's worth noting that extremely strong winds can sometimes blow pollen away from ground level, causing a temporary drop in pollen concentrations in some localised areas.


Rain offers a contrast to the effect of wind on pollen counts. Raindrops can capture airborne pollen and bring it down to the ground. This often results in decreased pollen levels during and immediately after rainfall.

People who are allergic to pollen might find temporary relief during these periods. However, this relief can be short-lived. Once the rain subsides and the ground begins to dry, the captured pollen can become airborne again, leading to a rebound in pollen counts. Moreover, rain can aid in plant growth, which could contribute to increased pollen production in the long term.


Temperature variations also contribute to changes in pollen counts. During the warmer months of the year, plants are more active and produce more pollen. Conversely, the colder months usually witness a decline in active pollen production and dispersal.

It is also essential to consider that unseasonal temperature changes can disrupt this cycle. A particularly mild winter or an early onset of spring temperatures can cause plants to start their pollinating phase sooner, thereby extending the allergy season for many individuals.

Combined Weather Events

Sometimes, a combination of weather conditions can create unique pollen scenarios. For instance, a rainy period followed by strong winds can first wash pollen out of the air and then redistribute it widely, causing fluctuations in pollen counts within a short period.

Furthermore, sudden changes in weather conditions, like moving from a cold front to a warm front, can also induce plants to release pollen in bursts, leading to spikes in pollen levels.

Understanding the role of weather in influencing pollen counts can be vital for individuals with pollen sensitivities.

This knowledge can guide their daily activities and help them take preventive measures to manage their symptoms effectively.

Can the pollen count in Toronto vary between different neighbourhoods or regions within the city?

The question of pollen count variations across different parts of Toronto is important for both residents and visitors, especially those susceptible to allergies. One major factor contributing to the disparity in pollen counts across the city is the type of vegetation in each area. Neighbourhoods that are abundant in trees, grasses, and flowering plants naturally generate higher pollen counts. Conversely, the more built-up urban centres, with their limited green spaces, tend to have lower pollen counts.

However, it is essential to consider the mobility of pollen. Pollen particles are lightweight and can be carried over distances by wind, meaning that even areas with low vegetation might experience elevated pollen counts if they are downwind of a more vegetated area. The wind direction and speed, therefore, become important variables in this context. The weather can also play a role; a strong gust of wind can stir up pollen and disperse it across various neighbourhoods, regardless of how much vegetation is in the immediate vicinity.

Microclimates also play a role in pollen count variations. For example, areas close to water bodies like Lake Ontario often experience different weather conditions compared to areas that are more inland. This is due to the moderating effect of the large water body on the local climate. The temperature near the lake is usually more stable, which can affect the timing and intensity of plant flowering and consequently, pollen release.

Proximity to parks or reserves can also significantly influence pollen counts. Toronto is home to numerous parks and green spaces, like High Park or the Toronto Islands, that have dense vegetation. Residents living near these areas are likely to experience higher pollen counts during the blooming seasons. In contrast, downtown areas like the Financial District or the Entertainment District, which have fewer green spaces, will typically have lower pollen counts, even though they may still be affected by pollen carried in from other regions.

Monitoring localised pollen counts is essential for understanding the risk level in each neighbourhood. Some advanced weather apps and healthcare platforms offer hyperlocal pollen count data, sometimes even at a street-level granularity. This can be invaluable for individuals with pollen allergies who need to take preventive measures such as limiting outdoor activities or taking antihistamines. Local healthcare providers and allergists often also have information on regional pollen levels, providing another reliable source for residents.

By considering these factors—vegetation types, wind patterns, microclimates, proximity to green spaces, and local monitoring services—residents can gain a nuanced understanding of how pollen counts might differ across Toronto's neighbourhoods and plan their activities accordingly.

Does the pollen count in Toronto impact the overall air quality index?

Pollen and the Air Quality Index (AQI) are often considered two separate matters. The AQI in Toronto, like in many other cities, is primarily designed to measure levels of pollutants that pose risks to human health and the environment. These pollutants include particulate matter, ozone, sulphur dioxide, and nitrogen dioxide, among others. Pollen, however, is not included in these measurements.

While pollen does not contribute to the AQI, its presence in the air can be a concern for individuals with allergies or respiratory issues. For people with sensitivities, high pollen levels can make the air feel 'unhealthy' even if the AQI indicates that the air quality is good. This perceived reduction in air quality can be misleading if one only considers the AQI.

High pollen counts often coincide with certain weather conditions, like dry and windy days, which are the same conditions that can elevate AQI levels. It might seem like a rise in pollen counts is correlated with a poor AQI, but they are tracked and assessed independently. In some cases, weather conditions conducive to high pollen counts can result in conditions that also increase AQI levels, like increased particulate matter, but this is not a direct relationship.

In terms of public health, pollen counts can be particularly impactful for those with pre-existing conditions, such as asthma or chronic obstructive pulmonary disease (COPD). In these individuals, high levels of pollen can exacerbate symptoms and can even lead to hospital visits. The relationship between pollen and respiratory conditions should not be underestimated. It can contribute to absenteeism from work and school and reduce overall quality of life, underlining the significance of monitoring pollen counts for susceptible populations.

Additionally, pollen can have indirect effects on indoor air quality. For example, keeping windows open on high-pollen days can lead to elevated indoor pollen levels, affecting individuals even in the relative safety of their homes. Air filters and purifiers can mitigate this to some extent but are not always 100% effective. Therefore, while pollen might not impact the AQI, it certainly plays a role in both outdoor and indoor air quality for certain populations.

It's important to note that there are specialised indices and monitoring systems specifically designed to track pollen levels. These can be useful tools for those who are sensitive to pollen, providing information that can guide daily activities and medication use. While these specialised indices run parallel to AQI measurements, they serve to highlight that air quality is a multifaceted issue, affected by a range of factors beyond traditional pollutants.

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