Myrtle Beach Weather in September

The hot summer weather at Myrtle Beach in South Carolina continues right into September.

This page gives detailed information on the typical September temperature, precipitation, sun, humidity and storms for Myrtle Beach. The temperature and rainfall numbers here are historical averages based on climate data gathered at Grand Strand Airport. The sunshine and humidity measurements are averages from Charleston International Airport.

Temperature Weather iconTemperature

83 °F September average high 28 °C
68 °F September average low 20 °C
25 days 80 °F max. or more (27 °C)
18 days 70 °F min. or less (21 °C)

Usually every day in September warms to over 70 degrees Fahrenheit (21 degrees Celsius) in Myrtle Beach. The city averages 2 days this month when the thermometer reaches into the 90s °F (over 32 °C). Temperatures above 100 °F (38 °C) are not expected here during September.

The thermometer dips to 60 °F (16 °C) or below on an average of 4 nights. But September only rarely gets as cold as 50 °F (10 °C).

Rainy Weather iconRain

6.7 in total precipitation 169 mm
11 days of rain

Half the time, Myrtle Beach receives 3.4 to 8.4 inches (87 to 213 mm) of rainfall in September. One in four years has drier weather, while another one in four is wetter.

Sunny Weather iconSun

61 % sunshine
7 days clear skies

The sun's rays reach the ground in Myrtle Beach during 61 percent of daylight hours on average in September, for a total of 226 hours in the month. Typically on 7 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in September at the seaside city lasts for 12 hours and 21 minutes a day on average. The longest day of the month is the 1st with 12 hours and 51 minutes of daylight. By the end of the month, the days have shortened to 11:52 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

78 % September average humidity

The relative humidity in Myrtle Beach during September usually peaks at 90 percent in the morning then drops to 61 percent by early afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 89 90 89 70 61 63 77 86

Stormy Weather iconStorms

3 days rainfall of 0.5 inches (13 mm) or more
12 % chance a named storm approaches

There's a 6 percent probability that a hurricane will approach within 100 miles (165 km) of Myrtle Beach during September. The chance of a major category 3 to 5 hurricane reaching the area is 2 percent.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals. The named storm probabilities come from the Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.

Myrtle Beach Weather
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