Mercer Island Historic Weather Records
Analyse hottest, coldest, windiest & wettest days

Mercer Island Weather Trend Graph

Temperature (°C)

Months

Months	Historic Min Temp.	Min Temp.	Forecasted Min Temp.	Historic Max Temp.	Max Temp.	Forecasted Max Temp.
	0.5687500000000001	-1.5		6.41875	6.4
	0.83125	3.7		6.1499999999999995	8.6
	1.5	7.4		6.9937499999999995	9.5
	2.4375	6.2		7.012500000000001	9.4
	3.075	4.2		7.1125	6.3
	2.375	4		7.64375	6.5
	2.35625	4.3		7.0249999999999995	5.9
	2.61875	2.1		7.312499999999999	5.5
	2.2187500000000004	4.5		7.668749999999999	8.9
	2.05625	2.9		7.156250000000001	9.9
	2.1875	6.7		7.3375	8.7
	2.21875	8.9		7.593750000000001	10.4
	1.9374999999999996	6.8		7.08125	12.9
	1.4562500000000003	6.2		7.4125000000000005	7.2
Jan.	1.7062500000000003	5		7.43125	8.4
	2.1687499999999997	2		7.500000000000001	11.3
	2.6062500000000006	2.5		7.50625	11.7
	2.86875	3.8		7.56875	11.1
	2.30625	3.6		7.7	11.5
	1.9937500000000004	0.9		8.043750000000001	5.6
	2.4312499999999995	-1.1		7.88125	5.5
	2.31875	-1.7		7.925000000000001	7.5
	2.7374999999999994	-1.2		7.968750000000001	7.8
	3.31875	-0.2		8.275	8
	2.7124999999999995	-2		8.962499999999999	5
	2.55625	-0.8		8.86875	7.2
	2.775	4.8		8.681249999999999	10.1
	2.9375	7		8.931250000000002	9.4
	3.093749999999999	7.8		8.55625	10.5
	3.18125	9.1		7.8500000000000005	10.3
	3.39375	8.9		7.96875	15.2
	2.4812500000000006	8.5		7.81875	9.9
	1.6875	8.7		8.087499999999999	9.5
	1.9124999999999994	7.7		7.243749999999999	12.6
	2.75	9.2		7.493749999999999	16.5
	2.5374999999999996	4		7.86875	17.4
	2.4812499999999997	6.2		7.8999999999999995	13.6
	1.78125	8.9		8.2	10.9
	1.7499999999999998	7.3		7.981249999999999	10.1
	1.8875000000000002	5.8		8.556250000000002	8.3
	1.3312499999999998	4.3		7.356250000000002	11.9
	1.9500000000000002	3.4		7.887499999999999	5.3
	2.7125000000000004	3.5		8.56875	5.4
	1.99375	5.7		8.243749999999999	8.1
	2.0812500000000003	4.5		8.081249999999999	7.1
Feb.	2.46875	2.6		7.7562500000000005	5.4
	2.5187500000000007	2.2		8.6875	5.1
	2.4250000000000003	0.5		8.762500000000001	5
	2.1625	0.2		7.63125	6.9
	2.08125	0		8.2	2.8
	2.0812500000000003	-0.9		8.63125	5.4
	1.6312499999999996	3.4		8.18125	5.4
	1.3375	7.2		7.725	13.6
	0.7	5.9		7.268750000000002	8
	0.98125	1.5		7.6	6.1
	0.93125	3.3		8.15625	6.6
	0.8875000000000002	5.4		8.362499999999999	7.6
	1.8125000000000004	5.3		8.756250000000001	7.2
	2.4500000000000006	-0.7		9.15	7.8
	2.48125	2.2		9.56875	14.3
	2.85	2.5		8.662500000000001	14.1
	2.6374999999999997	8.7		9.15	10.4
	2.09375	8.4		9.674999999999999	11
	2.7249999999999996	5.7		10.1625	7.1
	2.0312499999999996	6.2		9.581249999999999	9.4
	1.86875	8.7		9.0125	10.1
	2.10625	2.7		9.149999999999999	9.7
	2.0250000000000004	1.8		10.787499999999998	4.4
	2.5124999999999997	1.9		9.743749999999999	5.8
	2.9374999999999987	4.4		10.71875	9.3
	3.474999999999999	4.5		11.075	8.7
	3.85	1.3		10.2625	6.2
	4.075	2.4		9.975	6.2
Mar.	3.4437499999999996	-2.2		10.568750000000001	9.3
	3.0000000000000004	6.8		10.78125	11.4
	2.49375	9.7		11.243749999999999	12.1
	2.6687499999999997	10.6		11.812499999999998	11.9
	2.7375	10.3		12.662500000000001	12.2
	3.4124999999999996	9.7		12.575	12.5
	4.237500000000001	4.4		10.9	8.1
	3.5875000000000004	3		11.256249999999998	8.9
	3.6062500000000006	3.2		11.54375	9.3
	4.23125	4.8		12.0125	10
	4.2437499999999995	4.1		12.25625	7.7
	4.94375	2.9		12.368750000000004	10.2
	4.85625	1.7		12.95	11.3
	5.375	4.8		11.5875	9.8
	4.793749999999999	2.1		11.856250000000001	6.8
	4.7562500000000005	1.2		12.262500000000001	9.1
	4.40625	3.3		13.406250000000002	13.4
	4.43125	5.3		11.975	13
	4.237500000000001	4.4		12.337499999999999	10.8
	4.175	4.1		12.56875	15.8
	3.912499999999999	4.3		11.718749999999998	17.8
	4.2437499999999995	6.4		11.75	19.6
	4.800000000000001	7.3		12.149999999999997	21.5
	4.975	6.4		12.750000000000002	13.7
	4.7749999999999995	2.9		12.89375	15.6
	4.2124999999999995	3.9		13.40625	18.6
	5.125	6.2		12.66875	20.4
	4.25	8.1		12.7	13.7
	4.375	5.4		12.01875	13.3
	4.1	7		12.156249999999998	11.8
	3.7874999999999996	5.9		13.400000000000002	9.6
Apr.	4.11875	2.8		14.125	7.9
	5.0562499999999995	1.8		13.750000000000002	13.1
	5.05625	4		14.881249999999998	14.3
	5.100000000000001	5.2		15.35	19.2
	5.6000000000000005	8		14.931249999999999	21.3
	5.675	9.3		15.19375	22.2
	5.58125	9.5		15.28125	16.1
	5.475	8.8		14.6125	12.1
	5.6	6.7		15.062499999999998	13.4
	6.450000000000002	5.4		15.7	18.1
	6.3625	5		14.899999999999999	17.5
	6.5625	5.3		15.53125	20
	6.30625	8.3		13.900000000000002	15
	5.8687499999999995	7.2		14.193749999999998	15.4
	6.2250000000000005	6.4		16.168749999999996	21.9
	6.906250000000001	7.5		15.424999999999999	25
	6.1125	10.1		16.19375	24.4
	6.637500000000001	10.3		16.606250000000003	21.6
	7.118750000000001	11.5		16.85	26.2
	7.01875	11.7		16.40625	24.6
	6.8125	11.8		15.043750000000001	22.7
	7.18125	10.9		17.224999999999998	17.9
	7.275	9.2		16.7375	18.8
	6.975	8.2		17.662499999999998	18
	7.5625	8.4		18.525000000000002	22.4
	7.962499999999999	9.6		18.66875	18.4
	8.11875	9.5		19.275000000000006	20.6
	8.1375	9.5		18.962500000000002	27.3
	8.3	10		19.400000000000002	17.7
	9.2625	8.2		20.125000000000004	17.3
May	9.65625	7.5		19.425	13.7
	9.43125	6.9		18.71875	12.3
	9.0375	4.5		17.981250000000003	18.2
	8.6625	7.3		18.300000000000004	20.2
	8.45625	9.1		17.95	17.3
	8.274999999999999	7.8		18.0625	18.7
	8.31875	9.4		17.425	24.9
	8.74375	11.1		17.625	25.8
	8.868749999999999	10.6		17.4125	21
	8.6625	10.9		17.500000000000004	23.1
	8.937499999999998	10.3		17.9125	16.9
	9.331250000000002	8.7		18.512500000000003	16
	9.368750000000002	9.2		18.875	23.4
	9.543750000000001	12.3		19.25625	26.8
	9.493750000000002	9.7		18.15	11.7
	8.725	8.2		18.34375	18.5
	9.4875	7.1		19.71875	18.9
	9.65625	8.5		19.875	24.7
	10.61875	12.2		20.38125	30
	9.881250000000001	13.7		19.331249999999997	22.8
	9.71875	11.8		19.89375	19.6
	9.9875	9.9		20.39375	17.5
	10.012499999999998	8.4		21.412499999999998	15.8
	10.106250000000001	7.6		21.218749999999996	20.2
	10.775	8.9		21.275	19.5
	10.7	10.4		19.8	17.9
	10.206249999999999	9.4		19.362500000000004	18.7
	10.18125	8.6		20.106250000000003	22.1
	10.374999999999998	11.5		20.412500000000005	25.6
	10.6125	13		18.493749999999995	31
	10.024999999999999	15.1		18.30625	32.3
Jun.	9.4375	16.2		19.15	32.8
	9.562500000000002	13.5		20.000000000000004	23.6
	10.5	12.4		20.268750000000004	23.4
	10.818750000000001	11.2		19.81875	25.2
	10.487499999999999	13.5		19.8625	29
	10.568750000000001	11.9		20.031249999999996	23.7
	10.568749999999996	10.6		22.075	25.4
	11.537500000000001	12.6		22.331249999999997	28
	11.475	16.1		22.8625	31.4
	11.831249999999999	15.8		22.218749999999996	31.5
	11.912500000000001	12.7		22.89375	19.3
	12.287500000000001	12.6		23.76875	19
	12.793749999999998	11.6		23.343750000000004	20.1
	13.200000000000001	11.7		23.043750000000003	19.1
	12.975	11.4		23.59375	19
	12.787499999999998	11.8		24.3875	17.9
	13.3375	9.7		24.412500000000005	19.3
	13.168750000000001	10.9		23.056250000000002	19.9
	12.681250000000002	14.9		22.450000000000003	24.1
	11.90625	12.3		23.4625	21.2
	12.531249999999998	10.8		24.33125	23.6
	13.143749999999999	12		25.2875	29.1
	13.00625	12.8		24.74375	26.1
	13.362499999999999	13.4		25.54375	23.5
	13.825000000000003	13.5		25.799999999999997	28.2
	14.174999999999999	13.5		23.962500000000002	27.1
	13.325000000000001	12.3		25.1375	22.3
	13.593750000000002	12.3		25.256249999999998	21.5
	13.74375	10.3		25.2125	25.5
	13.387500000000001	11.6		25.4875	29.1
Jul.	13.71875	13.4		26.0375	28.6
	14.33125	13.4		25.55	23.5
	13.906250000000002	12.5		24.70625	24.3
	13.8	12.9		25.012500000000003	24.4
	13.28125	11.8		24.9875	24.2
	13.862499999999999	13.5		24.975	29.5
	13.725000000000001	17.1		25.287499999999998	37.3
	13.50625	17		25.400000000000002	34.6
	13.537500000000001	15.9		24.718749999999996	27
	13.625	14.5		24.8125	27.7
	13.593750000000002	14.2		25.150000000000006	23.9
	14.00625	14.9		26.375	23.1
	13.75	13.9		26.118750000000006	27.6
	13.925	14.8		27.237500000000004	23.2
	14.5	12.8		27.65	25.1
	15.168749999999998	11.9		27.95	26.8
	15.34375	13		26.8	28.4
	15.093749999999998	14.6		26.493750000000002	23.8
	14.73125	12.3		26.024999999999995	21.2
	14.837500000000002	10.5		25.8	24.2
	14.762499999999998	12.8		26.800000000000004	26.6
	15.03125	13.4		27.374999999999996	30
	15.375	14.4		26.993750000000002	29.9
	14.35625	14.6		25.36875	29.7
	14.387499999999998	15.3		25.150000000000002	31
	14.612499999999997	13.3		25.29375	26
	14.974999999999998	12.8		25.724999999999998	25.1
	14.975000000000001	13.5		26.087500000000002	28
	14.575000000000003	15.3		27.03125	28.4
	14.793750000000003	13.6		26.25	27.4
	15.00625	13.6		26.137500000000003	27.1
Aug.	15.262500000000003	14.7		25.981250000000003	28.8
	14.91875	14.5		26.94375	29.5
	15.1	12.8		27.206250000000004	25.9
	14.968750000000002	13.8		26.975	28.6
	15.006249999999998		13.5	25.874999999999996		29.6
	14.10625		15.3	25.6125		30.7
	13.999999999999998		17.7	25.275000000000006		29.2
	13.9375		13.5	24.312500000000004		20.9
	13.50625		13.4	24.2875		25.4
	13.350000000000003		14.5	24.2875		28.4
	13.524999999999999		14.9	25.337500000000002		27.8
	13.787499999999998		13.6	25.112500000000004		25.1
	14.093750000000002		14	25.362499999999997		24.7
	13.75		13.5	24.49375		24.8
	13.4625		13.5	23.256249999999998		23.4
	13.18125		13.2	22.6375		22.7
	13.00625		13.3	21.78125		22
	13.00625		13	23.175		23.3
	12.56875		12.6	24.199999999999996		24
	13.199999999999998		13	24		23.8
	12.55625		12.4	23.48125		23.8
	13.18125		13.1	24.89375		24.7
	13.54375		13.7	24.56875		24.4
	13.50625		13.3	23.9875		23.7
	13.55625		13.1	23.493750000000002		23.5
	13.243749999999999		12.8	23.30625		22.5
	12.831249999999995		12.9	23.312500000000004		23.3
	12.981250000000003		12.9	23.743750000000002		23.3
	12.83125		12.8	22.506249999999998		23.1
	11.925000000000002		12	21.912499999999994		22.5
	11.525		12	22.30625		22.1
Sep.	11.924999999999999		11.9	21.6125		21.7
	11.418750000000001		11.7	21.86875		21.9
	11.987499999999999		12.2	20.45625		19.7
	11.893749999999999		11.8	19.187499999999996		19.8
	11.587499999999999			20.43125
	11.749999999999998			20.34375
	11.2875			21.25
	10.943750000000001			20.1625
	11.5875			19.4
	11.474999999999998			20.037499999999998
	11.275			19.55625
	11.200000000000003			18.918750000000003
	10.975			19.749999999999996
	10.71875			19.1625
	10.225			18.831249999999997
	9.86875			18.256249999999998
	9.487499999999999			18.818750000000005
	9.475			18.187500000000004
	9.468750000000002			17.73125
	9.368749999999999			18.2125
	9.30625			17.60625
	9.39375			19.1625
	9.85625			18.574999999999996
	9.606250000000001			17.95625
	9.718749999999998			16.9125
	9.0875			16.499999999999996
	8.293750000000001			15.556250000000002
	7.543749999999999			15.631250000000001
	7.60625			16.6625
	8.34375			16.08125
Oct.	8.6625			16.55
	8.799999999999999			16.9625
	8.306249999999999			15.793750000000001
	8.36875			15.606250000000001
	8.65625			16.150000000000002
	8.643749999999999			15.356249999999996
	8.399999999999999			15.2125
	7.94375			14.399999999999999
	7.04375			14.118750000000002
	7.3187500000000005			13.40625
	6.8875			12.724999999999998
	6.0249999999999995			12.1875
	6.4375			12.85625
	7.006249999999999			12.731250000000001
	6.89375			13.456249999999999
	6.63125			13.237499999999999
	6.6187499999999995			12.637500000000001
	6.606250000000001			12.0625
	6.143749999999999			12.575
	6.268750000000001			11.899999999999999
	6.950000000000001			12.656249999999998
	6.85625			12.387500000000001
	6.01875			11.424999999999999
	5.456250000000001			10.868749999999999
	5.19375			11.374999999999998
	5.206250000000001			10.76875
	4.937499999999999			10.631249999999998
	4.643750000000001			10.73125
	5.25			10.7375
	6.068749999999999			10.556249999999999
	5.9437500000000005			10.875
Nov.	4.9750000000000005			10.349999999999998
	4.1812499999999995			9.63125
	3.7875			9.56875
	3.9437500000000005			9.487499999999999
	3.4749999999999996			8.925
	2.8312500000000003			8.862499999999999
	3.6624999999999996			9.3
	3.9750000000000005			9.2125
	2.9749999999999996			8.600000000000001
	2.8499999999999996			7.8500000000000005
	3.54375			8.40625
	4.46875			9.249999999999998
	4.0874999999999995			9.31875
	2.925			8.23125
	2.0625			7.36875
	2.4124999999999996			7.31875
	2.9499999999999993			8.062499999999998
	2.45			7.38125
	2.41875			7.3812500000000005
	2.21875			7.412500000000001
	2.14375			7.5375
	2.31875			7.562500000000001
	3.075			7.9875
	3.16875			8.137500000000001
	2.975			7.481249999999999
	3.26875			7.675
	3.3562499999999997			7.537499999999999
	3.4937500000000004			7.61875
	2.9312500000000004			7.43125
	2.7749999999999995			7.3875
Dec.	2.6			7.025000000000001
	2.4187499999999997			7.0125
	2.6437500000000003			7.1812499999999995
	2.8499999999999996			7.275000000000001
	2.7375000000000003			6.843749999999999
	2.8437499999999996			6.868750000000001
	2.7437499999999995			6.949999999999999
	2.3249999999999997			6.6812499999999995
	1.9625000000000001			6.918749999999999
	2.11875			6.325
	1.7562500000000003			6.1812499999999995
	1.275			5.5062500000000005
	1.8875			5.956250000000001
	2.462500000000001			6.4750000000000005
	2.1			6.974999999999999
	1.4999999999999998			5.981250000000001
	0.6066666666666668			5.746666666666667

Max Temp.

Historic Max Temp.

Min Temp.

Historic Min Temp.

Yearly Summary 2026

37°C

Highest Temp

21 Jul. 26

-2°C

Lowest Temp

15 Mar. 26

Seasonal Breakdown

Hottest MonthAugust27.29°C

Coldest MonthJanuary3.7°C

Wettest MonthMarch7.77mm

Windiest MonthMarch14.3km/h

Mercer Island Climate Change InsightsSee how climate patterns are evolving over time. Temperature shifts, rainfall trends, and extreme events—all in one place.

Weather City Ranking GloballyExplore Real time of the world’s hottest & Coldest Cities based on current temperature data.

Frequently Asked Questions

1. What is the hottest month in Mercer Island historically?

August is historically Mercer Island's hottest month, with average maximum temperatures around 26°C. During peak heatwave events, the highest recorded temperatures have reached 41°C on 2021-06-28.

2. What is the coldest month in Mercer Island historically?

February is Mercer Island's coldest month, with average minimum temperatures around 2°C. The all-time record low of -11°C was recorded on 2010-11-24.

3. What is the average annual rainfall in Mercer Island over the past 17 years?

Mercer Island's average annual rainfall is approximately 1264.7mm, based on records spanning 17 years.

4. How many rainy days does Mercer Island experience on average per year?

Mercer Island historically records approximately 197.2 rainy days per year. November has the highest number of rain days at an average of 20.7 days.

5. What is the all-time highest temperature ever recorded in Mercer Island?

The all-time highest temperature recorded in Mercer Island is 41°C on 2021-06-28.

6. What is the all-time lowest temperature ever recorded in Mercer Island?

The all-time lowest temperature recorded in Mercer Island is -11°C on 2010-11-24.

7. What is the windiest time of year in Mercer Island historically?

Mercer Island experiences its strongest winds during November. The historic gust record of 43.8 kph was recorded on 2017-11-13.

8. What is the highest and lowest humidity in Mercer Island during a year?

Usually, Mercer Island's humidity peaks in December at around 85.2% and drops to its lowest in July at approximately 67.2%.

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Mercer Island Historic Weather Records
Analyse hottest, coldest, windiest & wettest days

Mercer Island Weather Trend Graph

Yearly Summary 2026

Seasonal Breakdown

Frequently Asked Questions

Recent Blogs On Weather

London's July 2026 Heatwave: From 20°C to 34°C in Weeks

World Top 10 Hottest Cities Are All in India Again - May 2026

Delhi Air Quality 2026 vs 6-Year Historical PM2.5 Data

What 17 Years of Delhi Temperature Data Reveal About May's Heatwave Escalation

World Top Hottest Cities Belong to India - April 2026

Construction Air Pollution: The Invisible Hazard Reshaping India's Urban Air

Kitchen Air Pollution: How Cooking Can Spike Your Indoor AQI

Mumbai Air Quality Comparison of 2025 Vs 2026 (Jan-Feb)

Why AQI Standards Vary Across the World - And Why Air Quality Index Matters More Than Ever

Why Winter Suffocates and Monsoon Saves Delhi Air Quality 2025?

Winter vs Summer Air: Why Air Pollution Behaves So Differently Across Seasons

Mercer Island Historic Weather RecordsAnalyse hottest, coldest, windiest & wettest days

Mercer Island Weather Trend Graph

Yearly Summary 2026

Seasonal Breakdown

Frequently Asked Questions

Recent Blogs On Weather

London's July 2026 Heatwave: From 20°C to 34°C in Weeks

World Top 10 Hottest Cities Are All in India Again - May 2026

Delhi Air Quality 2026 vs 6-Year Historical PM2.5 Data

What 17 Years of Delhi Temperature Data Reveal About May's Heatwave Escalation

World Top Hottest Cities Belong to India - April 2026

Construction Air Pollution: The Invisible Hazard Reshaping India's Urban Air

Kitchen Air Pollution: How Cooking Can Spike Your Indoor AQI

Mumbai Air Quality Comparison of 2025 Vs 2026 (Jan-Feb)

Why AQI Standards Vary Across the World - And Why Air Quality Index Matters More Than Ever

Why Winter Suffocates and Monsoon Saves Delhi Air Quality 2025?

Winter vs Summer Air: Why Air Pollution Behaves So Differently Across Seasons

Mercer Island Historic Weather Records
Analyse hottest, coldest, windiest & wettest days