Portland, ME weather in September
Expect mild weather with some rain in Portland in September, with highs near 71°F and lows near 52°F. Rain falls on about 9 days. Great for outdoor plans.
- Normal high
- 71°F
- Normal low
- 52°F
- Wet days
- 9
- 3.8 in total
- Muggy days
- 2
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 76°F | 66°F |
| Normal low | 57°F | 47°F |
| Chance of a wet day | 30% | 32% |
| Sunrise / sunset | 6:04 am / 7:17 pm | 6:37 am / 6:24 pm |
| Daylight | 13.2 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 am55°Fdew point 51°F
- 9 am64°Fdew point 54°F
- Noon68°Fdew point 53°F
- 3 pm68°Fdew point 53°F
- 6 pm63°Fdew point 53°F
- 9 pm59°Fdew point 53°F
NOAA hourly normals (local standard time) from Portland Intl Jetport (2 mi away); average wind 7 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F17 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph3 of 30
- Hot dayshigh 90°F or more1 of 30
- Muggy daysdaily mean dew point 65°F or more2 of 30
- Wet daysat least 0.01 in of rain or melted snow9 of 30
- Notable rainat least 0.10 in5 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 3.8 in; a dry September brings about 2.3 in and a wet one about 4.5 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How September varies from year to year
- Warmest September, 1991-20202015: average high 76°F
- Coolest September1995: average high 67°F
- Wettest September2008: 10.8 in
- Driest September2019: 0.4 in
- Highest reading93°F (September 11, 2013)
- Lowest reading30°F (September 29, 1995)
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 | 79°F | 71°F | 60°F |
| Normal low | 60°F | 52°F | 41°F |
| Wet days | 9 | 9 | 11 |
| Comfortable days | 12 | 17 | 6 |
| Daylight | 13.9 h | 12.5 h | 11.0 h |
Highs change by -8°F from August and -11°F into October.
Nearby alternatives in September
- Cooler: Lake Placid, NY190 mi · high 66°F · 12 wet days
How Portland ranks in September
- Normal high337th warmest of 378 cities; 1st of 5 in Maine
- Wet days267th driest of 378
- Comfortable days42nd most of 342
What to pack for Portland in September
- A rain jacket or umbrella – rain on about 9 days
Heating and cooling
September has 145 heating degree days and 43 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Portland in September?
The normal high is 71°F and the normal low is 52°F. From 1991 to 2020 the hottest September reading was 93°F (most recently on September 11, 2013).
Does it rain a lot in Portland in September?
About 9 days in September have at least 0.01 in of precipitation, and the normal total is 3.8 in. The wettest September in 1991-2020 was in 2008 (10.8 in); the driest was in 2019 (0.4 in).
Is September a good time to visit Portland?
September ranks 2nd of 12 months on our comfort score for Portland (71 out of 100). It has about 17 comfortable days and about 1 day at 90°F or hotter. The best months are June and September.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates and humidity and wind by hour: Portland Intl Jetport (USW00014764), 2.4 mi WSW of the city center, 45 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Portland International Jetport Airport (726060-14764), 2.8 mi WSW of the city center, 44 ft . Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).