Opportunity weather in September

In September, Opportunity sees average daytime highs of 73°F and overnight lows near 49°F, with 0.9 in of precipitation across 4.4 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 78°F in the first days to 68°F by the end. The sky is clear or mostly clear about 50% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 12 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Opportunity's 3rd-clearest and 9th-windiest month. For the whole year in context, see Opportunity's year-round climate.

Daytime high: 73°; 4th warmest
Overnight low: 49°; 9th coldest
Precipitation: 0.9 in; 4.4 wet days
Daylight: 12 h 18 min; 5:33 AM – 5:53 PM
Cloud cover: 41%; 3rd clearest
Wind: 5 mph; 9th windiest
Solar energy: 4.72 kWh/m²
Travel score: 7.8; out of 10

Opportunity is neighborhood of Spokane Valley, Washington, United States.

Density: 1,496/km²; people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

← August Opportunity year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 78°F in the first days to 68°F by the end.

A typical September day in Opportunity reaches about 73°F in the afternoon and slips back to 49°F overnight — a 24°F spread between the day's warmth and the night's chill. On most days the high lands between 61°F and 85°F. Set against its neighbours, September runs about 10°F cooler than August and about 15°F warmer than October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°F)	78	78	78	77	77	77	76	76	75	75	75	74	74	73	73	73	72	72	72	71	71	70	70	70	69	69	68	68	67	67
Avg low (°F)	53	53	52	52	52	52	51	51	51	51	50	50	50	49	49	49	49	48	48	48	47	47	47	47	46	46	46	45	45	45

	Avg high (°F)	Avg low (°F)
1	78	53
2	78	53
3	78	52
4	77	52
5	77	52
6	77	52
7	76	51
8	76	51
9	75	51
10	75	51
11	75	50
12	74	50
13	74	50
14	73	49
15	73	49
16	73	49
17	72	49
18	72	48
19	72	48
20	71	48
21	71	47
22	70	47
23	70	47
24	70	47
25	69	46
26	69	46
27	68	46
28	68	45
29	67	45
30	67	45

How September really feels in Opportunity

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F

heat index over the day's high

Days feeling ≤ 32°F

wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Opportunity weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

Month	High / Low (°F)	Rainfall (inches)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	35° / 25°	3.1	13.3	8.9	8.7	0.0
Feb	40° / 26°	2.1	10.6	6.3	9.9	0.0
Mar	48° / 31°	2.7	12.8	4.1	11.6	1.6
Apr	57° / 37°	2.3	11	1.2	13.3	3.8
May	66° / 45°	2.0	8.6	0	14.9	6.3
Jun	73° / 51°	1.5	6.6	0	15.7	7.2
Jul	84° / 57°	0.6	3	0	15.4	7.0
Aug	83° / 57°	0.5	2.6	0	14.1	7.2
Sep	73° / 49°	0.9	4.4	0.1	12.4	7.8
Oct	58° / 39°	2.0	8.5	0.3	10.6	4.5
Nov	43° / 31°	3.3	13.2	5	9.1	0.6
Dec	35° / 25°	3.4	12.8	9	8.3	0.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 50% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 33%. Skies tend to cloud over as the month goes on.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	75	75	75	73	73	72	71	70	69	67	67	66	66	65	64	64	64	64	64	64	64	64	64	64	64	64	63	63	62	62
Cloudier (%)	25	25	25	27	27	28	29	30	31	33	33	34	34	35	36	36	36	36	36	36	36	36	36	36	36	36	37	37	38	38

	Clearer (%)	Cloudier (%)
1	75	25
2	75	25
3	75	25
4	73	27
5	73	27
6	72	28
7	71	29
8	70	30
9	69	31
10	67	33
11	67	33
12	66	34
13	66	34
14	65	35
15	64	36
16	64	36
17	64	36
18	64	36
19	64	36
20	64	36
21	64	36
22	64	36
23	64	36
24	64	36
25	64	36
26	64	36
27	63	37
28	63	37
29	62	38
30	62	38

Chance of precipitation in September

Any precipitation

Opportunity gets around 0.9 in of rain and snow over 4.4 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 15% and peaks near 18% on the wettest days, and about 0 day brings snow. The odds climb toward the end of the month.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	10	10	10	10	11	11	11	12	13	14	14	15	16	16	16	17	17	17	17	17	18	18	18	18	18	17	17	18	18	18

	Rain chance (%)
1	10
2	10
3	10
4	10
5	11
6	11
7	11
8	12
9	13
10	14
11	14
12	15
13	16
14	16
15	16
16	17
17	17
18	17
19	17
20	17
21	18
22	18
23	18
24	18
25	18
26	17
27	17
28	18
29	18
30	18

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	98	98	98	98	98	98	98	98	99	99	99	99	99	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100
Comfortable (%)	2	2	2	2	2	2	2	2	1	1	1	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

	Dry (%)	Comfortable (%)
1	98	2
2	98	2
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	99	1
10	99	1
11	99	1
12	99	1
13	99	1
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	100	0
30	100	0

Wind in September

Winds average 5 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (mph)	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (mph)	Feels
1	5	calm
2	5	calm
3	5	calm
4	5	calm
5	5	calm
6	5	calm
7	5	calm
8	5	calm
9	5	calm
10	5	calm
11	5	calm
12	5	calm
13	5	calm
14	5	calm
15	5	calm
16	5	calm
17	5	calm
18	5	calm
19	5	calm
20	5	calm
21	5	calm
22	5	calm
23	5	calm
24	5	calm
25	5	calm
26	5	calm
27	5	calm
28	5	calm
29	5	calm
30	5	calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 12 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 102 minutes over September. Sunrise moves from 5:12 AM to 5:53 AM, and sunset from 6:25 PM to 5:24 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	13.2	13.2	13.1	13.0	13.0	12.9	12.9	12.8	12.7	12.7	12.6	12.6	12.5	12.5	12.4	12.3	12.3	12.2	12.2	12.1	12.0	12.0	11.9	11.9	11.8	11.7	11.7	11.6	11.6	11.5
Sunrise (AM)	5:12	5:14	5:15	5:16	5:18	5:19	5:21	5:22	5:23	5:25	5:26	5:28	5:29	5:30	5:32	5:33	5:35	5:36	5:37	5:39	5:40	5:42	5:43	5:44	5:46	5:47	5:49	5:50	5:51	5:53
Sunset (PM)	6:25	6:23	6:21	6:19	6:17	6:15	6:13	6:10	6:08	6:06	6:04	6:02	6:00	5:58	5:56	5:53	5:51	5:49	5:47	5:45	5:43	5:41	5:38	5:36	5:34	5:32	5:30	5:28	5:26	5:24

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.2	5:12	6:25
2	13.2	5:14	6:23
3	13.1	5:15	6:21
4	13.0	5:16	6:19
5	13.0	5:18	6:17
6	12.9	5:19	6:15
7	12.9	5:21	6:13
8	12.8	5:22	6:10
9	12.7	5:23	6:08
10	12.7	5:25	6:06
11	12.6	5:26	6:04
12	12.6	5:28	6:02
13	12.5	5:29	6:00
14	12.5	5:30	5:58
15	12.4	5:32	5:56
16	12.3	5:33	5:53
17	12.3	5:35	5:51
18	12.2	5:36	5:49
19	12.2	5:37	5:47
20	12.1	5:39	5:45
21	12.0	5:40	5:43
22	12.0	5:42	5:41
23	11.9	5:43	5:38
24	11.9	5:44	5:36
25	11.8	5:46	5:34
26	11.7	5:47	5:32
27	11.7	5:49	5:30
28	11.6	5:50	5:28
29	11.6	5:51	5:26
30	11.5	5:53	5:24

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.72 kWh/m².

For context, solar energy here swings from a low near 1.06 kWh/m² to a high of 7.56 kWh/m² in July across the year — September's 4.72 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	5.6	5.5	5.5	5.4	5.3	5.3	5.2	5.2	5.1	5.0	5.0	4.9	4.8	4.8	4.7	4.7	4.6	4.5	4.5	4.4	4.4	4.3	4.3	4.2	4.1	4.1	4.0	4.0	3.9	3.8
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	5.6	Bright
2	5.5	Bright
3	5.5	Bright
4	5.4	Bright
5	5.3	Bright
6	5.3	Bright
7	5.2	Bright
8	5.2	Bright
9	5.1	Bright
10	5.0	Bright
11	5.0	Bright
12	4.9	Bright
13	4.8	Bright
14	4.8	Bright
15	4.7	Bright
16	4.7	Bright
17	4.6	Bright
18	4.5	Bright
19	4.5	Bright
20	4.4	Bright
21	4.4	Bright
22	4.3	Bright
23	4.3	Bright
24	4.2	Bright
25	4.1	Bright
26	4.1	Bright
27	4.0	Bright
28	4.0	Moderate
29	3.9	Moderate
30	3.8	Moderate

Planning a trip in September

Is September a good time to visit Opportunity?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.8

Sightseeing

1st-best month of the year

5.7

Beach & pool

3rd-best month of the year

September is one of the better times to visit Opportunity for general sightseeing.

What to pack for Opportunity in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Opportunity sees daytime highs around 73°F and nights near 49°F. Worth packing: light clothes and sun protection. About 4 days see rain.

light clothessun protection

UV index in Opportunity in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Opportunity peaks around July 17 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	1	2	4	5	7	6	9	6	4	3	1	1
Level	Low	Low	Moderate	Moderate	High	High	Very high	High	Moderate	Moderate	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	2	Low
Mar	4	Moderate
Apr	5	Moderate
May	7	High
Jun	6	High
Jul	9	Very high
Aug	6	High
Sep	4	Moderate
Oct	3	Moderate
Nov	1	Low
Dec	1	Low

Air quality in Opportunity in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Opportunity is worst in August — around 30 µg/m³ PM2.5 (moderate), about 4.9× the cleanest month (December, 6 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	7	8	10	11	11	10	13	30	20	11	11	6
Level	Good	Good	Good	Good	Good	Good	Moderate	Moderate	Moderate	Good	Good	Good

	PM2.5 (µg/m³)	Level
Jan	7	Good
Feb	8	Good
Mar	10	Good
Apr	11	Good
May	11	Good
Jun	10	Good
Jul	13	Moderate
Aug	30	Moderate
Sep	20	Moderate
Oct	11	Good
Nov	11	Good
Dec	6	Good

Location & terrain

Where is Opportunity?

Opportunity sits at 47.6°N, 117.2°W, 2,005 ft above sea level, in United States. The nearest listed city is Spokane Valley, 1.9 mi away.

Topography around Opportunity

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Opportunity.

Within 2 miles, the terrain around Opportunity has only modest variations in elevation — a maximum elevation change of 276 ft around an average of 2,034 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 3,524 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 5,023 ft.

The land around Opportunity is covered by artificial surfaces (49%) and trees (35%) within 2 miles, trees (43%) and grassland (27%) within 10 miles, and trees (51%), cropland (23%) and grassland (22%) within 50 miles.

2 miles

276 ft

artificial surfaces 49%

10 miles

3,524 ft

trees 43%

50 miles

5,023 ft

trees 51%

treesgrasslandcroplandartificial surfacesbare terrainwater

← August Opportunity year-round climate October →Best places to visit in September

September weather nearby: Spokane Valley 1.9 mi · Spokane 8.7 mi · Post Falls 14 mi · Coeur d'Alene 22 mi · Pullman 63 mi · Moscow 65 mi · Lewiston 86 mi · Lewiston Orchards 89 mi

United States travel facts

Power plugs: Type A / B; 120 V · 60 Hz
Prices: ≈ 100% of US; price level, 2025
GDP per capita: $90,027; 2025
Happiness: 6.8 / 10; World Happiness, 2025
Safe drinking water: 98%; of population, 2024
Homicide rate: 5.8; per 100k, 2023
Road deaths: 12.7; per 100k/yr, 2019
Income group: High; World Bank
Religion

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Opportunity (47.6499°, -117.2399°, elevation 2,005 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).

	Avg high (°F)	Avg low (°F)
1	78	53
2	78	53
3	78	52
4	77	52
5	77	52
6	77	52
7	76	51
8	76	51
9	75	51
10	75	51
11	75	50
12	74	50
13	74	50
14	73	49
15	73	49
16	73	49
17	72	49
18	72	48
19	72	48
20	71	48
21	71	47
22	70	47
23	70	47
24	70	47
25	69	46
26	69	46
27	68	46
28	68	45
29	67	45
30	67	45

	Clearer (%)	Cloudier (%)
1	75	25
2	75	25
3	75	25
4	73	27
5	73	27
6	72	28
7	71	29
8	70	30
9	69	31
10	67	33
11	67	33
12	66	34
13	66	34
14	65	35
15	64	36
16	64	36
17	64	36
18	64	36
19	64	36
20	64	36
21	64	36
22	64	36
23	64	36
24	64	36
25	64	36
26	64	36
27	63	37
28	63	37
29	62	38
30	62	38

	Rain chance (%)
1	10
2	10
3	10
4	10
5	11
6	11
7	11
8	12
9	13
10	14
11	14
12	15
13	16
14	16
15	16
16	17
17	17
18	17
19	17
20	17
21	18
22	18
23	18
24	18
25	18
26	17
27	17
28	18
29	18
30	18

	Dry (%)	Comfortable (%)
1	98	2
2	98	2
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	99	1
10	99	1
11	99	1
12	99	1
13	99	1
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	100	0
30	100	0

	Avg high (°F)	Avg low (°F)
1	78	53
2	78	53
3	78	52
4	77	52
5	77	52
6	77	52
7	76	51
8	76	51
9	75	51
10	75	51
11	75	50
12	74	50
13	74	50
14	73	49
15	73	49
16	73	49
17	72	49
18	72	48
19	72	48
20	71	48
21	71	47
22	70	47
23	70	47
24	70	47
25	69	46
26	69	46
27	68	46
28	68	45
29	67	45
30	67	45

	Clearer (%)	Cloudier (%)
1	75	25
2	75	25
3	75	25
4	73	27
5	73	27
6	72	28
7	71	29
8	70	30
9	69	31
10	67	33
11	67	33
12	66	34
13	66	34
14	65	35
15	64	36
16	64	36
17	64	36
18	64	36
19	64	36
20	64	36
21	64	36
22	64	36
23	64	36
24	64	36
25	64	36
26	64	36
27	63	37
28	63	37
29	62	38
30	62	38

	Rain chance (%)
1	10
2	10
3	10
4	10
5	11
6	11
7	11
8	12
9	13
10	14
11	14
12	15
13	16
14	16
15	16
16	17
17	17
18	17
19	17
20	17
21	18
22	18
23	18
24	18
25	18
26	17
27	17
28	18
29	18
30	18

	Dry (%)	Comfortable (%)
1	98	2
2	98	2
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	99	1
10	99	1
11	99	1
12	99	1
13	99	1
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	100	0
30	100	0

	Avg high (°F)	Avg low (°F)
1	78	53
2	78	53
3	78	52
4	77	52
5	77	52
6	77	52
7	76	51
8	76	51
9	75	51
10	75	51
11	75	50
12	74	50
13	74	50
14	73	49
15	73	49
16	73	49
17	72	49
18	72	48
19	72	48
20	71	48
21	71	47
22	70	47
23	70	47
24	70	47
25	69	46
26	69	46
27	68	46
28	68	45
29	67	45
30	67	45

	Clearer (%)	Cloudier (%)
1	75	25
2	75	25
3	75	25
4	73	27
5	73	27
6	72	28
7	71	29
8	70	30
9	69	31
10	67	33
11	67	33
12	66	34
13	66	34
14	65	35
15	64	36
16	64	36
17	64	36
18	64	36
19	64	36
20	64	36
21	64	36
22	64	36
23	64	36
24	64	36
25	64	36
26	64	36
27	63	37
28	63	37
29	62	38
30	62	38

	Rain chance (%)
1	10
2	10
3	10
4	10
5	11
6	11
7	11
8	12
9	13
10	14
11	14
12	15
13	16
14	16
15	16
16	17
17	17
18	17
19	17
20	17
21	18
22	18
23	18
24	18
25	18
26	17
27	17
28	18
29	18
30	18

	Dry (%)	Comfortable (%)
1	98	2
2	98	2
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	99	1
10	99	1
11	99	1
12	99	1
13	99	1
14	100	0
15	100	0
16	100	0
17	100	0
18	100	0
19	100	0
20	100	0
21	100	0
22	100	0
23	100	0
24	100	0
25	100	0
26	100	0
27	100	0
28	100	0
29	100	0
30	100	0