South Portland weather
Temperature, rain and wind in South Portland (Maine, United States), a city of about 25,556 people: how it is right now, hour by hour into tomorrow, the next 7 days and what each month of the year is like.
This page is not in Google’s index: the city is small, or it gets the same forecast as a large city next to it.
Right now
Friday 16 October, 00:00 (America/New_York)
49 °F
Partly cloudy
Feels like
46 °F
Humidity
73%
Wind
7 mph
NE · Beaufort 2
Dew point
40 °F
Cloud cover
90%
Pressure
1,021 hPa
Hour by hour
Next 24 hours, in the city’s local time.
| Time | Conditions | Temperature | Rain | Wind |
|---|---|---|---|---|
| 23:00 | Partly cloudy | 49 °F | 0.00 in | 5 mph |
| 00:00 | Partly cloudy | 49 °F | 0.00 in | 7 mph |
| 01:00 | Partly cloudy | 48 °F | 0.00 in | 6 mph |
| 02:00 | Cloudy | 48 °F | 0.00 in | 7 mph |
| 03:00 | Cloudy | 49 °F | 0.00 in | 8 mph |
| 04:00 | Partly cloudy | 50 °F | 0.00 in | 11 mph |
| 05:00 | Cloudy | 49 °F | 0.00 in | 11 mph |
| 06:00 | Cloudy | 50 °F | 0.00 in | 13 mph |
| 07:00 | Cloudy | 52 °F | 0.00 in | 18 mph |
| 08:00 | Cloudy | 54 °F | 0.00 in | 20 mph |
| 09:00 | Light rain | 55 °F | 0.01 in | 22 mph |
| 10:00 | Heavy rain | 55 °F | 0.07 in | 20 mph |
| 11:00 | Rain | 54 °F | 0.02 in | 19 mph |
| 12:00 | Light rain | 55 °F | 0.01 in | 22 mph |
| 13:00 | Light rain | 56 °F | 0.01 in | 22 mph |
| 14:00 | Cloudy | 58 °F | 0.00 in | 22 mph |
| 15:00 | Rain | 60 °F | 0.02 in | 21 mph |
| 16:00 | Rain | 60 °F | 0.02 in | 19 mph |
| 17:00 | Heavy rain | 60 °F | 0.05 in | 18 mph |
| 18:00 | Heavy rain showers | 61 °F | 0.16 in | 17 mph |
| 19:00 | Rain | 62 °F | 0.02 in | 19 mph |
| 20:00 | Cloudy | 63 °F | 0.00 in | 18 mph |
| 21:00 | Cloudy | 63 °F | 0.00 in | 17 mph |
| 22:00 | Cloudy | 63 °F | 0.00 in | 17 mph |
Next 7 days
| Day | Conditions | Low | High | Rain outlook |
|---|---|---|---|---|
| Thu 15/10 | Partly cloudy | 48 °F | 50 °F | no rain expected · 0.00 in |
| Fri 16/10 | Light rain | 48 °F | 63 °F | rain possible · 0.38 in |
| Sat 17/10 | Fair | 35 °F | 60 °F | no rain expected · 0.00 in |
| Mon 19/10 | Partly cloudy | 41 °F | 55 °F | no rain expected · 0.00 in |
| Tue 20/10 | Cloudy | 42 °F | 58 °F | no rain expected · 0.00 in |
| Wed 21/10 | Clear sky | 45 °F | 57 °F | no rain expected · 0.00 in |
| Thu 22/10 | Cloudy | 43 °F | 51 °F | rain unlikely · 0.01 in |
This column is our own reading: the global model does not publish a probability of precipitation for this region, so we classify the day from the forecast symbol and the total in millimetres. It is not an official probability figure.
America/New_York
What each number means
- Rain (mm)
- 1 millimetre of rain is 1 litre of water per square metre. Up to 2 mm in a day is drizzle; from 10 mm it is proper rain; more than 50 mm in a few hours is the amount that floods streets.
- Humidity
- Relative humidity is how much water vapour the air holds compared with the most it can hold at that temperature. Above 80% sweat evaporates slowly and heat feels worse; below 30% your throat and eyes dry out.
- Dew point
- The dew point is the temperature at which the air would start to condense. The closer it is to the air temperature, the muggier it feels. Above 20 °C the air already feels heavy.
- Feels like
- "Feels like" combines temperature, wind and humidity: strong wind carries heat away from the body, so it feels colder than the thermometer; high humidity in the heat makes it feel warmer.
- Wind
- Wind is given as a speed and the direction it blows from. Up to 20 km/h you barely notice it; at 40 km/h it moves branches and parasols; above 60 km/h it brings down trees and roof tiles.
- Cloud cover
- Cloud cover as a percentage is how much of the sky is covered. Up to 20% is a clear sky; above 80% the sun barely gets through.
- Chance of rain
- The model does not publish a probability of precipitation for this region. This column is our own reading: the global model does not publish a probability of precipitation for this region, so we classify the day from the forecast symbol and the total in millimetres. It is not an official probability figure.
Month-by-month climate
In October, South Portland averages 53 °F and about 5.7 in of rain over the month, on the 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025) climatology.
Warmest month
August
Coldest month
January
Wettest month
October
Driest month
August
| Month | Mean temperature | Rain | Mean humidity |
|---|---|---|---|
| January | 30 °F | 4.1 in | 85% |
| February | 30 °F | 4.1 in | 83% |
| March | 35 °F | 4.3 in | 81% |
| April | 42 °F | 4.8 in | 83% |
| May | 50 °F | 4.0 in | 87% |
| June | 59 °F | 5.0 in | 88% |
| July | 66 °F | 3.8 in | 88% |
| August | 67 °F | 3.7 in | 86% |
| September | 62 °F | 3.8 in | 83% |
| October | 53 °F | 5.7 in | 81% |
| November | 44 °F | 4.9 in | 81% |
| December | 36 °F | 5.6 in | 83% |
Frequently asked questions
- Will it rain tomorrow in South Portland?
- rain possible. Rain: 0.38 in. Low 48 °F, High 63 °F.
- What is the temperature in South Portland right now?
- 49 °F, partly cloudy. Feels like: 46 °F. Humidity: 73%.
- What will the weather be like at the weekend in South Portland?
- Sat 17/10: fair, 35 °F / 60 °F, no rain expected.
- Which is the wettest month in South Portland?
- October — ~5.7 in (25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025), NASA POWER).
- How far ahead does this South Portland forecast go?
- This page shows 7 days. The model run used here is from 16/10/2026, 01:18 UTC, and the page fetches a new one every 30 minutes.
Nearby cities
Forecasts for places near South Portland:
- Portland 2 km
- South Portland Gardens 6 km
- Westbrook 11 km
- West Scarborough 14 km
- Saco 23 km
- Biddeford 24 km
- Brunswick 38 km
- Sanford 49 km
How to read this page
How to read the min and the max
The week’s high (63 °F) arrives in the afternoon, about two hours after solar noon; the low (35 °F) just before sunrise. Both are air temperature in the shade, two metres above ground — in direct sun or over asphalt a thermometer reads higher.
Where this number comes from
The South Portland forecast comes from MET Norway, a partir do ECMWF HRES e, na área nórdica, do MEPS, run of 16/10/2026, 01:18 UTC. The month-by-month climate comes from NASA POWER, climatology of 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025). Both are credited in full at the foot of this page.
What a forecast cannot promise
Out to two days accuracy is high; by day seven the trend matters more than the exact figure. For South Portland the model publishes no rain probability, so the expectation column is our reading.
Severe weather warnings
This page is informational. For official warnings of storms, gales or flooding affecting South Portland, go to your national weather service through the World Meteorological Organization warning portal.
Understanding the weather and climate of South Portland
Is this week in South Portland above or below the October normal?
The average of the next 7 days in South Portland works out at 50 °F, against a normal of 53 °F for October over 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025). That is 35 °F below typical, a modest gap and well within week-to-week variation.
Within the week the highest maximum lands on Fri 16/10 (63 °F) and the lowest minimum on Sat 17/10 (35 °F). Forecast rain adds up to 0.39 in, roughly 7% of everything South Portland gets in an average October (5.7 in). The wettest day is Fri 16/10, with 0.38 in.
When is the wettest and the driest month in South Portland?
On the 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025) climatology, the wettest month in South Portland is October, at about 5.7 in, and the driest is August, at 3.7 in. The two extremes differ by only 1.5 times, which means rain is spread fairly evenly across the year in South Portland. For October, the month you are reading this in, the average is 5.7 in.
What does the dew point say about how South Portland feels?
Right now in South Portland the air is at 49 °F with a dew point of 40 °F and relative humidity of 73%. With the two values that close, sweat evaporates slowly and the heat weighs more than the thermometer suggests — that is the working definition of muggy.
What is the climate of South Portland like through the year?
The warmest month in South Portland is August (67 °F on average) and the coldest is January (30 °F), a swing of about 21 °C around an annual mean of 48 °F. A swing of this size means a genuinely temperate climate: summer and winter call for different clothes, different housing and different habits.
Because South Portland lies in the northern hemisphere, at 43.64° north, summer falls in June, July and August, in the middle of the calendar.
How far is South Portland from Boston?
The nearest large city to South Portland is Boston, about 157 km away in a straight line, to the south-west, with 653,833 inhabitants. At that distance it is already common for South Portland and Boston to have different days, because a front or a squall line takes hours to cross the gap. Being larger, Boston shows up in more searches, and plenty of people end up reading its forecast assuming it covers South Portland.
Words on this page
Apparent temperature
The temperature the body actually feels, rather than the one on the thermometer. It combines air temperature with wind, which carries heat away faster, and humidity, which slows the evaporation of sweat. That is why 30 °C in dry air with a breeze is easier than 28 °C in still, muggy air.
Dew point
The temperature air would have to cool to, at constant pressure and moisture, for water to start condensing. The closer the dew point sits to the air temperature, the less room the vapour has and the muggier the day feels.
Millimetre of rain
The depth of water rain would leave on a flat surface with no run-off. One millimetre is one litre per square metre, no matter how large the area measured is.
Standard definition by World Meteorological Organization (WMO) · Millimetre of rain
Relative humidity
How much water vapour the air holds compared with the most it could hold at that temperature, as a percentage. Because that ceiling rises with heat, the same amount of vapour reads high at dawn and low in the afternoon.
Climate normal
The average of a climate element — temperature, rainfall, humidity — computed over a long, standardised period, usually thirty years. It does not predict anything: it says what is typical for that place in that month, and gives you a ruler for calling a week warm or wet.
Standard definition by World Meteorological Organization (WMO) · Climate normal
Forecast model
A program that solves the equations of the atmosphere on a grid of points and steps forward in time from the state observed now. Your city forecast is the model value at the nearest grid point, which is why two neighbouring towns get almost the same numbers.
Standard definition by MET Norway (Meteorologisk institutt) · Forecast model
Model run
The time the model was executed with the latest observations. Every forecast belongs to a run, and runs age: one from six hours ago knows nothing about the shower that started afterwards. It is the first thing to check when two sources disagree.
Standard definition by MET Norway (Meteorologisk institutt) · Model run
Source, model and licence
- Model
- MET Norway, a partir do ECMWF HRES e, na área nórdica, do MEPS
- Model run
- 16/10/2026, 01:18 UTC
- Source
- MET Norway (Meteorologisk institutt) — Locationforecast 2.0 — Based on data from MET Norway. Licence: CC BY 4.0 / NLOD 2.0.
- Month-by-month climate
- NASA POWER — Climatology (MERRA-2, 2001–2020) — The data was obtained from National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project — Climatology API v2. Dados públicos da NASA, citação obrigatória.
- Cities, coordinates and population
- Dados de cidades: GeoNames (CC BY 4.0)
The page fetches fresh data every 30 minutes. Informational content. For severe weather warnings, follow your country’s official weather service and civil protection authority.