Portland weather in August: Portland, Maine: normal highs, lows, rain and records for August
Portland in August has a normal high of 79°F and a normal low of 60°F, a daily mean of 69°F, falling from 80°F on the 1st to 76°F by the 31st. Measurable precipitation falls on 9 days in a normal August, 3.57 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 26°C and low of 15°C, 91 mm of precipitation in August.
- NOAA stationPortland International Jetport
- Station IDUSW00014764
- Location43.65°N 70.30°W
- Elevation45 ft (14 m)
- From the center6 miles
- Population69,568
- Jan 32° 16°
- Feb 35° 17°
- Mar 42° 26°
- Apr 54° 35°
- May 64° 46°
- Jun 74° 55°
- Jul 80° 61°
- Aug 79° 60°
- Sep 71° 52°
- Oct 60° 41°
- Nov 48° 32°
- Dec 38° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Portland in August?
The normal high is 79°F and the normal low 60°F, for a daily mean of 69.2°F. August is 1.2°F cooler than July and 7.6°F warmer than September. August is the 2nd warmest month of the year in Portland and the 9th wettest. Across the month the normal high falls 4°F, from 80°F on August 1 to 76°F on August 31. From one year to the next August's mean temperature typically moves about 1.6°F either way (NOAA's standard deviation), so roughly two Augusts in three average between 68°F and 71°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 33%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| August 1 | 80°F | 62°F | 33% | 20% |
| August 8 | 80°F | 61°F | 32% | 19% |
| August 15 | 79°F | 60°F | 31% | 18% |
| August 22 | 78°F | 59°F | 30% | 17% |
| August 31 | 76°F | 57°F | 30% | 16% |
Every day of August: normal high, low and chance of precipitation (warmest afternoon August 1, coldest night August 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| August 1 | 80°F | 62°F | 33% | 20% | 14 h 40 min |
| August 2 | 80°F | 61°F | 33% | 19% | 14 h 30 min |
| August 3 | 80°F | 61°F | 32% | 19% | 14 h 30 min |
| August 4 | 80°F | 61°F | 32% | 19% | 14 h 30 min |
| August 5 | 80°F | 61°F | 32% | 19% | 14 h 30 min |
| August 6 | 80°F | 61°F | 32% | 19% | 14 h 30 min |
| August 7 | 80°F | 61°F | 32% | 19% | 14 h 20 min |
| August 8 | 80°F | 61°F | 32% | 19% | 14 h 20 min |
| August 9 | 80°F | 61°F | 32% | 18% | 14 h 20 min |
| August 10 | 80°F | 61°F | 31% | 18% | 14 h 20 min |
| August 11 | 80°F | 61°F | 31% | 18% | 14 h 10 min |
| August 12 | 79°F | 60°F | 31% | 18% | 14 h 10 min |
| August 13 | 79°F | 60°F | 31% | 18% | 14 h 10 min |
| August 14 | 79°F | 60°F | 31% | 18% | 14 h 10 min |
| August 15 | 79°F | 60°F | 31% | 18% | 14 h |
| August 16 | 79°F | 60°F | 31% | 17% | 14 h |
| August 17 | 79°F | 60°F | 31% | 17% | 14 h |
| August 18 | 79°F | 60°F | 31% | 17% | 13 h 50 min |
| August 19 | 79°F | 60°F | 31% | 17% | 13 h 50 min |
| August 20 | 79°F | 59°F | 30% | 17% | 13 h 50 min |
| August 21 | 78°F | 59°F | 30% | 17% | 13 h 50 min |
| August 22 | 78°F | 59°F | 30% | 17% | 13 h 40 min |
| August 23 | 78°F | 59°F | 30% | 17% | 13 h 40 min |
| August 24 | 78°F | 59°F | 30% | 16% | 13 h 40 min |
| August 25 | 78°F | 58°F | 30% | 16% | 13 h 40 min |
| August 26 | 78°F | 58°F | 30% | 16% | 13 h 30 min |
| August 27 | 77°F | 58°F | 30% | 16% | 13 h 30 min |
| August 28 | 77°F | 58°F | 30% | 16% | 13 h 30 min |
| August 29 | 77°F | 58°F | 30% | 16% | 13 h 20 min |
| August 30 | 77°F | 57°F | 30% | 16% | 13 h 20 min |
| August 31 | 76°F | 57°F | 30% | 16% | 13 h 20 min |
- Normal high
- 79°FAugust average
- Normal low
- 60°FAugust average
- Precipitation
- 3.57 inmonth total
- Days with precipitation
- 90.01 inch or more
- Days at 90°F or more
- 1
- Daylight
- 14 h 40 min to 13 h 20 minAugust 1 to August 31
- Days at 70°F or more
- 29
- Days at 80°F or more
- 13
- Sunshine
- 79%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014764; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Portland in August?
On a given August day the chance of 0.01 inch or more is 31% on average, highest around August 1 (33%). In all, 3.57 in falls on 9 days of a normal August, 1 of them with an inch or more.
In a normal August in Portland, 1 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014764.
How humid and windy is Portland in August?
At 3 p.m. the normal temperature is 73°F with 57% relative humidity and a dew point of 57°F; at 6 a.m. it is 60°F with 88% humidity. The wind averages 6.5 mph, most often from the south in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 60°F | 56°F | 88% | 4.6 mph | – |
| 9 a.m. | 69°F | 58°F | 66% | 7.4 mph | 62% |
| noon | 74°F | 57°F | 56% | 9.6 mph | 55% |
| 3 p.m. | 73°F | 57°F | 57% | 10.4 mph | 54% |
| 6 p.m. | 69°F | 58°F | 68% | 7.3 mph | 59% |
| 9 p.m. | 64°F | 57°F | 79% | 4.7 mph | 68% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014764. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for August in Portland?
The warmest August temperature on Portland's official record (since 1874) is 103°F, on August 2, 1975; the coldest is 33°F, on August 31, 1965. The wettest August brought 15.22 in (1991).
The August mean against the 1991-2020 normal of 69.2°F: 2021 70.9°F (+1.7), 2022 72.1°F (+2.9), 2023 67.3°F (−1.9), 2024 68.2°F (−1.0), 2025 67.6°F (−1.6), 2026 70.5°F (+1.3). 3 of 6 ran warmer than normal.
| August | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 70.9°F | +1.7°F | 2.19 in |
| 2022 | 72.1°F | +2.9°F | 5.63 in |
| 2023 | 67.3°F | −1.9°F | 5.80 in |
| 2024 | 68.2°F | −1.0°F | 3.95 in |
| 2025 | 67.6°F | −1.6°F | 0.53 in |
| 2026 | 70.5°F | +1.3°F | 2.71 in |
Source: records: ACIS, NWS threaded record PWMthr; recent months: ACIS, station USW00014764. Records and recent months use complete months only.
How does August in Portland compare across Maine?
Across the 42 places PlainClimate covers in Maine, August normal highs run from 74°F in Limestone to 81°F in Fryeburg; Portland's is 79°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.