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September Weather in Ithaca, United States

Last updated: June 24, 2025

In September, the average temperature in Ithaca, United States is a pleasant 18°C (65°F). Expect the mercury to dip as low as 1°C (35°F) on cooler days, while it can soar up to 35°C (95°F) during warmer spells. Prepare for some rain too, with 104 mm (4.1 in) of precipitation spread across about 11 days. Don't forget, humidity averages a sticky 80%, making it feel warmer than it is.

September Temperature in Ithaca

In September in Ithaca, the average temperature is 18°C (65°F). Maximums can reach 35°C (95°F), and minimums can be as low as 1°C (35°F). This diverse temperature range makes Ithaca an ideal destination for travelers seeking both warm and cool experiences.

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

The chart illustrates September temperature patterns in Ithaca, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ithaca, September typically has an average temperature of 18°C (65°F), with highs reaching up to 35°C (95°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec252636465969747264523831
Data source: Temperature data for Ithaca 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 Ithaca

In Ithaca in September, the precipitation amount is 104 mm (4.1 in) over the course of 11 days.

September Precipitation Trends in Ithaca

The chart displays monthly precipitation patterns in Ithaca, 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 Ithaca, September typically receives around 104 mm (4.1 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec5963608811612163711041155962
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Ithaca

In Ithaca in September, humidity is 80%. With an average temperature of 18°C (65°F), this humidity feels like wandering through a warm, damp blanket, making every step slightly heavy and resulting in a constant sheen of sweat, which can be both refreshing and exhausting for travelers.

September Average Humidity in Ithaca

This chart illustrates the average monthly humidity levels in Ithaca, 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 Ithaca is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%85%86%80%80%80%81%80%84%90%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Ithaca

In Ithaca 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 Ithaca.

Maximum UV Index Levels in Ithaca for September

The chart shows the monthly maximum UV Index (UVI) for Ithaca 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 Ithaca typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24589101097532
Data source: Ithaca 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 Ithaca Compares to Other Months

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

This table compares monthly weather conditions in Ithaca, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)59 mm (2.3 inches)88%low
February Weather-3°C (26°F)63 mm (2.5 inches)87%moderate
March Weather2°C (36°F)60 mm (2.4 inches)85%moderate
April Weather8°C (46°F)87 mm (3.4 inches)86%very high
May Weather15°C (59°F)116 mm (4.6 inches)80%very high
June Weather21°C (69°F)120 mm (4.7 inches)80%very high
July Weather23°C (75°F)63 mm (2.5 inches)80%very high
August Weather22°C (72°F)71 mm (2.8 inches)80%very high
September Weather18°C (65°F)104 mm (4.1 inches)80%high
October Weather11°C (53°F)114 mm (4.5 inches)84%moderate
November Weather3°C (38°F)59 mm (2.3 inches)89%moderate
December Weather-1°C (31°F)62 mm (2.4 inches)86%low

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