September 2026 saw slightly warmer than average conditions for the month on Grandfather Mountain, according to data recorded at the park’s official weather reporting stations. Two weather records were broken during the month, both related to temperature.
The average high temperature for September 2026 was 65.46 degrees Fahrenheit, with an average low of 56.04 degrees and a mean of 60.75 degrees. The average low of 56.04 degrees broke the record for the warmest September average low ever recorded at Grandfather. The previous record was 54.27 degrees from September 2007. The September 2026 average high temperature and average mean temperature were also slightly above average. The 70-year averages for September temperatures at Grandfather Mountain include an average high temperature of 63.2 degrees, an average low temperature of 51.1 degrees and a mean of 57.1 degrees.
The warmest temperature recorded last month was 75.9 degrees on Sept. 4. Grandfather’s record high temperature for September is 79 degrees, observed Sept. 10, 1979. The highest temperature ever recorded in Grandfather’s 70 years as a weather reporting station, 83.2 degrees on July 1, 2012.
A daily high temperature record was broken on Sept. 2 with a reading of 75.7 degrees. The previous record for that day was 75 degrees in 1984.
Sept. 26 saw the coldest temperature recorded last month with a low temperature reading of 43.7 degrees. The lowest temperature ever observed on Grandfather Mountain in the month of September is 24 degrees on Sept. 30, 1967.
The weather station on the Mile High Swinging Bridge noted zero days in September with a wind gust higher than 60 mph. On Sept. 27, the weather station at the top recorded the month’s highest wind gust of 46 mph, while the month’s highest recorded sustained wind speed clocked in at 34.7 mph that same day. The highest gust ever recorded on Grandfather Mountain was 124 mph, observed Feb. 25, 2019.
The weather station near the Swinging Bridge reported 6.35 inches of precipitation in Sept. 2026. Precipitation at the top of the mountain includes rain and the liquid equivalent of any frozen precipitation (when applicable). Due to wind, snow depth is not recorded at the top.
Observations recorded near the park’s Wilson Center for Nature Discovery totaled 7.90 inches of precipitation. Precipitation is also measured at the latter location, as high winds can make it difficult to record accurate observations at the top.
The mountain’s rainiest September was recorded in 2004, when 32.3 inches were observed near the bridge. The driest September on record was observed in 1984, when .86 inches were measured at the top.
There were 19 days of at least trace amounts of recorded liquid precipitation (rain and the liquid equivalent of frozen precipitation, when applicable) for September 2026. The record number of days for the month of September is 23 days, observed in 2020 and 2024.
The day with the highest amount of this precipitation observed was Sept. 7, when 1.57 inches were recorded at the top. The day with the highest amount of precipitation observed on record for September was Sept. 8, 2004, when the weather station noted 11.3 inches. Data from 2024’s Hurricane Helene is not taken into account for this record as staff were not able to record precipitation measurements in the immediate aftermath of the storm.
Weather Reporting
The Grandfather Mountain Stewardship Foundation records and reports data in two different ways:
- The park maintains an automated weather station at the top of the Mile High Swinging Bridge. The N.C. State Climate Office assists the foundation in calibrating the machines and ensuring overall accuracy of data.
- Grandfather Mountain has been an active member of the National Oceanic and Atmospheric Administration’s (NOAA) Cooperative Observer Program since 1956 by reporting weather data from locations near the Mile High Swinging Bridge and the Nature Museum (now the Wilson Center for Nature Discovery).
For more information on weather at Grandfather Mountain, visit www.grandfather.com/weather.