Mercer Island, WA vs Seattle, WA

Side-by-side comparison of monthly climate normals (NOAA 1991-2020).

Mercer Island is about the same temperature as Seattle (53.8°F vs 53.8°F annual avg) and similar rainfall to it (36.5 in vs 36.5 in per year). Both cities share a Warm-summer Mediterranean climate (Csb).

Mercer Island, WA

Annual avg
53.8°F
Annual precip
36.5 in
Warmest month
August (77.4°F)
Coldest month
December (36.2°F)
Annual swing
25.8°F
Pleasant months
4 / 12
Warm-summer Mediterranean Csb USDA Zone 9a

Seattle, WA

Annual avg
53.8°F
Annual precip
36.5 in
Warmest month
August (77.4°F)
Coldest month
December (36.2°F)
Annual swing
25.8°F
Pleasant months
4 / 12
Warm-summer Mediterranean Csb USDA Zone 9a

Best months to visit each city

Mercer Island

J
F
M
A
M
J
J
A
S
O
N
D

Seattle

J
F
M
A
M
J
J
A
S
O
N
D

Month-by-month comparison

Month Mercer Island Seattle
High Low Precip High Low Precip
January 48.6°F 36.8°F 5.21 in 48.6°F 36.8°F 5.21 in
February 50.7°F 36.8°F 3.71 in 50.7°F 36.8°F 3.71 in
March 54.8°F 39.4°F 3.94 in 54.8°F 39.4°F 3.94 in
April 59.8°F 43.6°F 2.89 in 59.8°F 43.6°F 2.89 in
May 66.5°F 49.3°F 1.98 in 66.5°F 49.3°F 1.98 in
June 71.2°F 54.0°F 1.22 in 71.2°F 54.0°F 1.22 in
July 77.3°F 57.5°F 0.56 in 77.3°F 57.5°F 0.56 in
August 77.4°F 58.1°F 0.83 in 77.4°F 58.1°F 0.83 in
September 71.7°F 53.9°F 1.37 in 71.7°F 53.9°F 1.37 in
October 61.0°F 46.4°F 3.49 in 61.0°F 46.4°F 3.49 in
November 53.0°F 39.9°F 5.80 in 53.0°F 39.9°F 5.80 in
December 47.8°F 36.2°F 5.49 in 47.8°F 36.2°F 5.49 in
Mercer Island overview
Full climate profile
 Seattle overview
Full climate profile