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September Weather in Markham, Canada

Last updated: June 18, 2025

In September, the average temperature in Markham, Canada is a pleasant 18°C (65°F). Expect minimums around 8°C (47°F) and maximums reaching 28°C (83°F). While you may enjoy some sunshine, be prepared for 69 mm (2.7 in) of precipitation spread over 9 days, resulting in an average humidity of 76%.

September Temperature in Markham

In September, in Markham, the average temperature is 18°C (65°F). Maximums can reach 28°C (83°F), while minimums can drop as low as 8°C (47°F). This makes Markham an ideal destination for travelers seeking mild weather and comfortable conditions during their visit.

September Weather in Markham: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Markham, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Markham, September typically has an average temperature of 18°C (65°F), with highs reaching up to 28°C (83°F) and lows dropping to around 8°C (47°F).
JanFebMarAprMayJunJulAugSepOctNovDec272733415061707065544032
Data source: Temperature data for Markham generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Markham

In Markham in September, the precipitation amount is 69 mm (2.7 in) spread over 9 days.

September Precipitation Trends in Markham

The chart displays monthly precipitation patterns in Markham, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Markham, September typically receives around 69 mm (2.7 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec808375118103807376691159691
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Markham

In Markham in September, humidity is 76%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace, making travel a little sticky but enjoyable, as long as you stay hydrated and take breaks in the shade.

September Average Humidity in Markham

This chart illustrates the average monthly humidity levels in Markham, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Markham is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%91%88%88%82%80%77%72%76%83%88%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Markham

In Markham in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Markham.

Maximum UV Index Levels in Markham for September

The chart shows the monthly maximum UV Index (UVI) for Markham in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Markham typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec245899987532
Data source: Markham September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Markham Compares to Other Months

Weather in Markham varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Markham, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Markham, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)80 mm (3.2 inches)91%low
February Weather-3°C (28°F)83 mm (3.3 inches)91%moderate
March Weather0°C (33°F)75 mm (2.9 inches)88%moderate
April Weather5°C (41°F)118 mm (4.6 inches)88%very high
May Weather10°C (50°F)103 mm (4.1 inches)82%very high
June Weather16°C (62°F)80 mm (3.1 inches)79%very high
July Weather21°C (71°F)73 mm (2.9 inches)77%very high
August Weather21°C (71°F)76 mm (3.0 inches)72%very high
September Weather18°C (65°F)69 mm (2.7 inches)76%high
October Weather12°C (54°F)115 mm (4.5 inches)83%moderate
November Weather4°C (40°F)96 mm (3.8 inches)88%moderate
December Weather0°C (33°F)91 mm (3.6 inches)87%low

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