Arcata weather in September: Arcata, California: normal highs, lows, rain and records for September
Arcata in September has a normal high of 65°F and a normal low of 49°F, a daily mean of 57°F, holding near 65°F all month. Measurable precipitation falls on 9 days in a normal September, 0.85 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 18°C and low of 9°C, 22 mm of precipitation in September.
- NOAA stationArcata Eureka Airport
- Station IDUSW00024283
- Location40.98°N 124.11°W
- Elevation200 ft (61 m)
- Population18,748
- Jan 56° 41°
- Feb 57° 41°
- Mar 57° 41°
- Apr 58° 43°
- May 60° 46°
- Jun 63° 49°
- Jul 63° 51°
- Aug 65° 51°
- Sep 65° 49°
- Oct 64° 45°
- Nov 59° 42°
- Dec 56° 40°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Arcata in September?
The normal high is 65°F and the normal low 49°F, for a daily mean of 56.8°F. September is 1.1°F cooler than August and 2.6°F warmer than October. September is the 3rd warmest month of the year in Arcata and the 10th wettest. From one year to the next September's mean temperature typically moves about 2.0°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 55°F and 59°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 34%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 65°F | 50°F | 23% | 3% |
| September 8 | 65°F | 49°F | 26% | 4% |
| September 15 | 65°F | 49°F | 29% | 6% |
| September 22 | 65°F | 48°F | 31% | 8% |
| September 30 | 65°F | 47°F | 34% | 10% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 12, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 65°F | 50°F | 23% | 3% | 13 h 10 min |
| September 2 | 65°F | 50°F | 23% | 3% | 13 h 10 min |
| September 3 | 65°F | 50°F | 23% | 3% | 13 h |
| September 4 | 65°F | 50°F | 24% | 3% | 13 h |
| September 5 | 65°F | 50°F | 24% | 4% | 13 h |
| September 6 | 65°F | 50°F | 25% | 4% | 13 h |
| September 7 | 65°F | 49°F | 25% | 4% | 12 h 50 min |
| September 8 | 65°F | 49°F | 26% | 4% | 12 h 50 min |
| September 9 | 65°F | 49°F | 26% | 4% | 12 h 50 min |
| September 10 | 65°F | 49°F | 26% | 5% | 12 h 50 min |
| September 11 | 65°F | 49°F | 27% | 5% | 12 h 40 min |
| September 12 | 65°F | 49°F | 27% | 5% | 12 h 40 min |
| September 13 | 65°F | 49°F | 28% | 5% | 12 h 40 min |
| September 14 | 65°F | 49°F | 28% | 6% | 12 h 30 min |
| September 15 | 65°F | 49°F | 29% | 6% | 12 h 30 min |
| September 16 | 65°F | 49°F | 29% | 6% | 12 h 30 min |
| September 17 | 65°F | 48°F | 30% | 7% | 12 h 30 min |
| September 18 | 65°F | 48°F | 30% | 7% | 12 h 20 min |
| September 19 | 65°F | 48°F | 30% | 7% | 12 h 20 min |
| September 20 | 65°F | 48°F | 30% | 7% | 12 h 20 min |
| September 21 | 65°F | 48°F | 31% | 7% | 12 h 20 min |
| September 22 | 65°F | 48°F | 31% | 8% | 12 h 10 min |
| September 23 | 65°F | 48°F | 31% | 8% | 12 h 10 min |
| September 24 | 65°F | 48°F | 32% | 8% | 12 h 10 min |
| September 25 | 65°F | 48°F | 32% | 8% | 12 h 10 min |
| September 26 | 65°F | 47°F | 32% | 9% | 12 h |
| September 27 | 65°F | 47°F | 33% | 9% | 12 h |
| September 28 | 65°F | 47°F | 33% | 9% | 12 h |
| September 29 | 65°F | 47°F | 33% | 10% | 11 h 50 min |
| September 30 | 65°F | 47°F | 34% | 10% | 11 h 50 min |
- Normal high
- 65°FSeptember average
- Normal low
- 49°FSeptember average
- Precipitation
- 0.85 inmonth total
- Days with precipitation
- 90.01 inch or more
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 6
- Days at 80°F or more
- 1
- Sunshine
- 79%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024283; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Arcata in September?
On a given September day the chance of 0.01 inch or more is 28% on average, highest around September 30 (34%). In all, 0.85 in falls on 9 days of a normal September.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024283.
How humid and windy is Arcata in September?
At 3 p.m. the normal temperature is 61°F with 70% relative humidity and a dew point of 52°F; at 6 a.m. it is 49°F with 94% humidity. The wind averages 4.8 mph, most often from the northwest in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 49°F | 48°F | 94% | 3.0 mph | – |
| 9 a.m. | 57°F | 51°F | 81% | 3.8 mph | – |
| noon | 61°F | 52°F | 72% | 8.2 mph | 57% |
| 3 p.m. | 61°F | 52°F | 70% | 9.4 mph | 59% |
| 6 p.m. | 57°F | 52°F | 82% | 5.6 mph | 57% |
| 9 p.m. | 53°F | 50°F | 91% | 3.1 mph | 57% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024283. 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 September in Arcata?
The warmest September temperature on this station's record (since 1945) is 96°F, on September 2, 2017; the coldest is 37°F, on September 25, 1993. The wettest September brought 4.37 in (2013).
The September mean against the 1991-2020 normal of 56.8°F: 2021 55.9°F (−0.9), 2022 57.8°F (+1.0), 2023 58.3°F (+1.5), 2024 56.8°F (at normal), 2025 59.5°F (+2.7), 2026 57.2°F (+0.4). 4 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 55.9°F | −0.9°F | 1.68 in |
| 2022 | 57.8°F | +1.0°F | 0.52 in |
| 2023 | 58.3°F | +1.5°F | 2.63 in |
| 2024 | 56.8°F | at normal | 0.13 in |
| 2025 | 59.5°F | +2.7°F | 2.15 in |
| 2026 | 57.2°F | +0.4°F | 1.00 in |
Source: records: ACIS, station USW00024283; recent months: ACIS, station USW00024283. Records and recent months use complete months only.
How does September in Arcata compare across California?
Across the 219 places PlainClimate covers in California, September normal highs run from 64°F in Eureka to 104°F in Brawley; Arcata's is 65°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.