average high/low temperature range in seattle
1 In spring time temperatures climb reaching 14.8Â°C (58.7Â°F) generally in the afternoon with overnight lows of 6.3Â°C (43.3Â°F). 2  During summer average high temperatures are 22.6Â°C (72.6Â°F) and average low temperatures are 13.1Â°C (55.6Â°F).eattle, Washington Climate & Temperature. 1  Seattle, Washington, Usa is at 47 36'N, 122 19'W, 60 m (197 ft).