Frederick, MD weather in September
September in Frederick: mild, with some rain. Highs 76°F, lows 58°F, about 9 wet days. A good month for most outdoor plans.
- Normal high
- 76°F
- Normal low
- 58°F
- Wet days
- 9
- 4.8 in total
- Muggy days
- 5
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 80°F | 70°F |
| Normal low | 62°F | 53°F |
| Chance of a wet day | 29% | 30% |
| Sunrise / sunset | 6:38 am / 7:41 pm | 7:04 am / 6:54 pm |
| Daylight | 13.1 h | 11.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical September day
- 6 am58°Fdew point 55°F
- 9 am67°Fdew point 58°F
- Noon74°Fdew point 57°F
- 3 pm77°Fdew point 57°F
- 6 pm72°Fdew point 57°F
- 9 pm65°Fdew point 58°F
NOAA hourly normals (local standard time) from Martinsburg E Wv Rgnl Airport (31 mi away); average wind 5 mph; clear or few clouds in 56% of daytime hours, mostly cloudy or overcast in 35%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F14 of 30
- Hot dayshigh 90°F or more1 of 30
- Muggy daysdaily mean dew point 65°F or more5 of 30
- Wet daysat least 0.01 in of rain or melted snow9 of 30
- Notable rainat least 0.10 in7 of 30
- Freezing nightslow 32°F or below0 of 30
- Snow on the groundsnow depth 1 in or more0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 4.8 in; a dry September brings about 2.6 in and a wet one about 6.2 in (25th and 75th percentiles). About 3 days bring half an inch or more, and about 2 an inch or more.
How September varies from year to year
- Warmest September, 1991-20201998: average high 82°F
- Coolest September2006: average high 71°F
- Wettest September2003: 12.0 in
- Driest September2005: 0.4 in
- Highest reading94°F (September 24, 2010)
- Lowest reading36°F (September 30, 1993)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 83°F | 76°F | 65°F |
| Normal low | 65°F | 58°F | 47°F |
| Wet days | 10 | 9 | 9 |
| Comfortable days | 5 | 14 | 13 |
| Daylight | 13.7 h | 12.4 h | 11.2 h |
Highs change by -7°F from August and -11°F into October.
Nearby alternatives in September
- Warmer: Washington, DC41 mi · high 81°F · 9 wet days
How Frederick ranks in September
- Normal high265th warmest of 378 cities; 3rd of 3 in Maryland
- Wet days245th driest of 378
- Comfortable days113th most of 342
What to pack for Frederick in September
- A rain jacket or umbrella – rain on about 9 days
Heating and cooling
September has 61 heating degree days and 111 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Frederick in September?
The normal high is 76°F and the normal low is 58°F. From 1991 to 2020 the hottest September reading was 94°F (most recently on September 24, 2010).
Does it rain a lot in Frederick in September?
About 9 days in September have at least 0.01 in of precipitation, and the normal total is 4.8 in. The wettest September in 1991-2020 was in 2003 (12.0 in); the driest was in 2005 (0.4 in).
Is September a good time to visit Frederick?
September ranks 3rd of 12 months on our comfort score for Frederick (66 out of 100). It has about 14 comfortable days and about 1 day at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall and snow depth: Damascus 3 Ssw (USC00182336), 14 mi SE of the city center, 700 ft (417 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Frost dates: Frederick Police Brks (USC00183348), 1.5 mi W of the city center, 380 ft (97 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: Martinsburg E Wv Rgnl Airport (USW00013734), 31 mi W of the city center, 534 ft (251 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Etrn Wv Rgnl/Shpherd Fd Airport (724177-13734), 30 mi W of the city center, 541 ft (258 ft higher than the city). Hourly observations, 1991-2020.