Issaquah weather in January

In January, Issaquah sees average daytime highs of 45°F and overnight lows near 35°F, with 8.3 in of precipitation across 18.7 wet days and about 8.7 hours of daylight. It is the 11th-warmest and 2nd-wettest month of the year here.

Highs climb over the month, from about 44°F in the first days to 47°F by the end. The sky is clear or mostly clear about 15% of the time in January, and the air most often feels dry.

Daylight stretches from about 8 h 18 min at the start of January to 9 h 12 min by month's end. Set against the rest of the year, January is Issaquah's 11th-clearest and 2nd-windiest month. For the whole year in context, see Issaquah's year-round climate.

Daytime high
45°
11th warmest
Overnight low
35°
2nd coldest
Precipitation
8.3 in
18.7 wet days
Daylight
8 h 36 min
7:58 AM – 4:37 PM
Cloud cover
76%
11th clearest
Wind
6 mph
2nd windiest
Solar energy
1.04 kWh/m²
Travel score
0.8
out of 10

Issaquah is city in King County, Washington, United States.

Density
1,222/km²
people per km²
Founded
1892

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

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 44°F in the first days to 47°F by the end.

A typical January day in Issaquah reaches about 45°F in the afternoon and slips back to 35°F overnight — a 10°F spread between the day's warmth and the night's chill. On most days the high lands between 37°F and 52°F. Set against its neighbours, January runs on par with December and about 3°F cooler than February.

20°30°40°50°60°151015202531
Avg high (°F)Avg low (°F)
14434
24435
34435
44435
54435
64435
74435
84435
94435
104435
114435
124535
134535
144535
154535
164535
174535
184535
194636
204636
214636
224636
234636
244636
254636
264636
274636
284736
294736
304736
314736

How January really feels in Issaquah

Once humidity and wind are folded in, January averages 0 days that feel above 90°F and 31 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
31
wind chill below the day's low

The story in January is cold — wind chill drags the overnight "feels like" below the raw low.

Issaquah weather by month

How January compares with the rest of the year at a glance. January is the 11th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan45° / 35°8.318.73.68.70.8
Feb48° / 36°5.815.52.69.91.5
Mar52° / 37°6.518.71.811.62.2
Apr57° / 41°5.416.50.213.33.4
May63° / 46°3.812.8014.95.1
Jun67° / 50°3.211.4015.75.9
Jul74° / 54°1.36.5015.47.7
Aug74° / 54°1.65.7014.17.9
Sep68° / 49°3.49012.46.6
Oct58° / 43°6.615.1010.63.9
Nov49° / 38°9.018.719.11.6
Dec44° / 35°8.118.43.48.30.6

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 15% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 9% of January, with mostly cloudy or overcast conditions the remaining 76%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12476
22476
32476
42476
52476
62476
72476
82476
92377
102476
112476
122476
132476
142476
152476
162476
172476
182476
192575
202575
212476
222476
232476
242476
252476
262476
272476
282476
292476
302476
312476

Chance of precipitation in January

Any precipitationSnow

Issaquah gets around 8.3 in of rain and snow over 18.7 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 59% and peaks near 61% on the wettest days, and about 4 days bring snow.

0%20%40%60%151015202531
Rain chance (%)Snow chance (%)
16015
26115
36115
46115
56115
66114
76114
86114
96114
106014
116014
126013
136013
145913
155912
165912
175811
185811
195811
205810
215810
225910
23599
24599
25598
26598
27598
28598
29598
30588
31588

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)
1100
2100
3100
4100
5100
6100
7100
8100
9100
10100
11100
12100
13100
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100
31100

Wind in January

Winds average 6 mph in January.

Across January, daily wind ranges from about 6 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 8 h 18 min at the start of January to 9 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 54 minutes over January. Sunrise moves from 8:02 AM to 7:45 AM, and sunset from 4:20 PM to 4:58 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
18.38:024:20
28.38:024:21
38.38:024:22
48.38:024:23
58.48:024:24
68.48:024:25
78.48:024:26
88.48:024:27
98.48:014:28
108.58:014:29
118.58:014:30
128.58:004:32
138.58:004:33
148.67:594:34
158.67:594:35
168.67:584:37
178.77:584:38
188.77:574:39
198.77:564:41
208.87:564:42
218.87:554:43
228.87:544:45
238.97:534:46
248.97:524:47
259.07:514:49
269.07:504:50
279.07:494:52
289.17:484:53
299.17:474:55
309.27:464:56
319.27:454:58

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 1.04 kWh/m².

For context, solar energy here swings from a low near 0.9 kWh/m² to a high of 6.18 kWh/m² in July across the year — January's 1.04 kWh/m² sits near the bottom.

00.511.52151015202531
Solar energy (kWh/m²)Level
10.9Dim
20.9Dim
30.9Dim
40.9Dim
50.9Dim
60.9Dim
70.9Dim
80.9Dim
91.0Dim
101.0Dim
111.0Dim
121.0Dim
131.0Dim
141.0Dim
151.0Dim
161.0Dim
171.1Dim
181.1Dim
191.1Dim
201.1Dim
211.1Dim
221.2Dim
231.2Dim
241.2Dim
251.2Dim
261.3Dim
271.3Dim
281.3Dim
291.3Dim
301.4Dim
311.4Dim
Planning a trip in January

Hazard calendar for Issaquah

In seasonPeak

In January, Issaquah sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Issaquah's rainy season runs October–April, when most of the year's rain falls.

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

Is January a good time to visit Issaquah?

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

0.8
Sightseeing
11th-best month of the year
0.0
Beach & pool
8th-best month of the year

January is a weaker month for outdoor sightseeing in Issaquah.

What to pack for Issaquah in January

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

In January, Issaquah sees daytime highs around 45°F and nights near 35°F. Pack a warm layer and rain gear. Worth having: a heavy coat. About 19 days see rain.

a warm layerrain geara heavy coat

UV index in Issaquah in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 1. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Issaquah peaks around July 17 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. 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 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 17UV 8Dec 17UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar4Moderate
Apr5Moderate
May7High
Jun6High
Jul8Very high
Aug6High
Sep4Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Issaquah in January

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Issaquah is worst in September — around 22 µg/m³ PM2.5 (moderate), about 3.4× the cleanest month (December, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodModerateGoodSep 1322 µg/m³Dec 177 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar12Moderate
Apr12Good
May11Good
Jun10Good
Jul10Good
Aug18Moderate
Sep22Moderate
Oct12Good
Nov8Good
Dec7Good
Location & terrain

Where is Issaquah?

Issaquah sits at 47.5°N, 122.0°W, 108 ft above sea level, in United States. The nearest listed city is West Lake Sammamish, 4.3 mi away.

Topography around Issaquah

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

Within 2 miles, the terrain around Issaquah has large variations in elevation — a maximum elevation change of 1,998 ft around an average of 512 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 3,002 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 14,413 ft.

The land around Issaquah is covered by trees (78%) within 2 miles, trees (77%) within 10 miles, and trees (76%) within 50 miles.

2 miles
1,998 ft
10 miles
3,002 ft
50 miles
14,413 ft
treesgrasslandartificial surfacesbare terrainwater
January weather nearby: West Lake Sammamish 4.3 mi · City of Sammamish 5.0 mi · Sammamish 8.1 mi · Fairwood 8.1 mi · Renton 9.3 mi · Mercer Island 9.3 mi · Maple Valley 9.3 mi · Bellevue 9.3 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
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

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 Issaquah (47.5301°, -122.0326°, elevation 108 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).