Portland climate

Portland Weather in September

NOAA 1991-2020 normals for Cashton, 6.9 km from Portland

Average highs run from 76°F on September 1 to 65°F on September 30, and lows from 58°F to 47°F. Normal precipitation for the month is 3.73 in over about 10 wet days.

September day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Portland, in °F, with the record for each date.020406080100151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
71°F
Average low
53°F
Precipitation
3.73 in
Record high
99°FSep 8, 1939
Record low
20°FSep 22, 1995
Chance of a freeze
9%
Daylight
13 h 12 min to 11 h 46 min
Cloud cover
55%
Humidity
74%
Dew point
52°F
Wind
9.8 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
Sep 176°F58°F96°F 193735°F 190931%0%
Sep 276°F58°F96°F 193740°F 196731%0%
Sep 376°F58°F98°F 193734°F 197431%0%
Sep 475°F57°F97°F 193735°F 197431%0%
Sep 575°F57°F94°F 202336°F 196231%0%
Sep 675°F57°F98°F 192236°F 196231%0%
Sep 775°F56°F95°F 192228°F 198631%0%
Sep 874°F56°F99°F 193930°F 190231%0%
Sep 974°F56°F95°F 193134°F 199532%0%
Sep 1074°F55°F97°F 195532°F 191732%0%
Sep 1173°F55°F98°F 193132°F 191732%0%
Sep 1273°F55°F95°F 193131°F 190232%0%
Sep 1373°F54°F93°F 193928°F 192332%0%
Sep 1472°F54°F96°F 193928°F 192332%0%
Sep 1572°F53°F97°F 193931°F 196633%0%
Sep 1671°F53°F98°F 193929°F 198433%0%
Sep 1771°F53°F94°F 193932°F 191633%0%
Sep 1871°F52°F91°F 194629°F 192933%0%
Sep 1970°F52°F93°F 189531°F 192933%0%
Sep 2070°F51°F95°F 194827°F 196233%0%
Sep 2169°F51°F90°F 190827°F 198233%0%
Sep 2269°F50°F93°F 193720°F 199533%0%
Sep 2368°F50°F94°F 193725°F 198333%0%
Sep 2468°F49°F89°F 193726°F 197633%0%
Sep 2567°F49°F86°F 201727°F 194234%0%
Sep 2667°F49°F87°F 201724°F 198434%0%
Sep 2767°F48°F83°F 192925°F 199134%0%
Sep 2866°F48°F86°F 190425°F 194233%0%
Sep 2966°F47°F85°F 189722°F 198433%0%
Sep 3065°F47°F85°F 189721°F 189933%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Portland, in percent, and of at least 0.1 inch of snowfall.0102030401102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (CDT).

September 1
sunrise 6:27 AM, sunset 7:39 PM
September 30
sunrise 7:00 AM, sunset 6:46 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00471280 (Cashton), public domain. Records: NOAA GHCN-Daily, station USC00478827, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.