September Weather in Ajax, Canada

Last updated: June 18, 2025

In Ajax, Canada, the average temperature in September is a pleasant 18°C (65°F). Expect a minimum of 9°C (49°F) and a maximum of 27°C (81°F), making it a month with mild variations. During this time, precipitation reaches approximately 73 mm (2.9 in) over 9 days, contributing to an average humidity of 76%. Perfect weather for exploring!

September Temperature in Ajax

In September in Ajax, the average temperature is 18°C (65°F). The maximum can reach 27°C (81°F), while the minimum can drop as low as 9°C (49°F). This pleasant climate makes Ajax an ideal destination for outdoor activities and sightseeing.

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

The chart illustrates September temperature patterns in Ajax, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ajax, September typically has an average temperature of 18°C (65°F), with highs reaching up to 27°C (81°F) and lows dropping to around 9°C (49°F).
JanFebMarAprMayJunJulAugSepOctNovDec272833404860707165554133
Data source: Temperature data for Ajax 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 Ajax

In Ajax in September, the precipitation amount is 73 mm (2.9 in), occurring over the course of 9 days.

September Precipitation Trends in Ajax

The chart displays monthly precipitation patterns in Ajax, 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 Ajax, September typically receives around 73 mm (2.9 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec8488771221057770787311810296
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Ajax

In Ajax 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 Ajax

This chart illustrates the average monthly humidity levels in Ajax, 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 Ajax 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 Ajax

In Ajax 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 Ajax.

Maximum UV Index Levels in Ajax for September

The chart shows the monthly maximum UV Index (UVI) for Ajax 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 Ajax typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec245899987532
Data source: Ajax 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 Ajax Compares to Other Months

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

This table compares monthly weather conditions in Ajax, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (28°F)84 mm (3.3 inches)91%low
February Weather-2°C (28°F)88 mm (3.5 inches)91%moderate
March Weather1°C (33°F)77 mm (3.0 inches)88%moderate
April Weather5°C (41°F)122 mm (4.8 inches)88%very high
May Weather9°C (49°F)105 mm (4.1 inches)82%very high
June Weather16°C (60°F)77 mm (3.0 inches)79%very high
July Weather21°C (70°F)70 mm (2.7 inches)77%very high
August Weather22°C (71°F)78 mm (3.1 inches)72%very high
September Weather18°C (65°F)73 mm (2.9 inches)76%high
October Weather13°C (55°F)118 mm (4.6 inches)83%moderate
November Weather5°C (41°F)102 mm (4.0 inches)88%moderate
December Weather1°C (33°F)96 mm (3.8 inches)87%low

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