Sammamish, Washington Weather History

Washington, United States  •  45 yrs data 📍 47.6044°N, 122.0412°W
°F / °C
☀️

Quick Climate Facts

(1981 – 2025)
Hottest Month
🔥
Aug
Avg 68.1°F
Min 46.4°F
Max 89.7°F
Coldest Month
❄️
Dec
Avg 32°F
Min 15.6°F
Max 48.5°F
Wettest Month
🌧️
Nov
271 mm
Driest Month
🏜️
Jul
36 mm
Most Humid
💧
Dec
92%
Least Humid
🌬️
Sep
76%
Highest Ever
🌡️
101.8°F
Jun 2021
Lowest Ever
🧊
-7.9°F
Feb 1989
Monthly Climate Data
Month 🌤️ High Low Avg Humid % Rain (mm) Wind (m/s) Solar (kWh/m²)

Showing average climate conditions across 45 years (1981–2025)

🌍 Weather in Sammamish Across Seasons

❄️ Winter in Sammamish

December is Sammamish's coldest month, with average lows reaching 15.6°F.
🌡️ December to February (avg)  ·  16.5°F50.4°F

🧥 Expect frosty nights and below-freezing temperatures during this Cold Winter period.

☀️ Summer in Sammamish

Summer temperatures in Sammamish peak in August, climbing to 89.8°F.
🌡️ July to September (avg)  ·  44.2°F88°F

🌤️ Early mornings and evenings are most comfortable during this Hot Summer season.

🌧️ Rainy Season in Sammamish

Sammamish sees its highest rainfall in November, receiving approximately 271 mm of precipitation.
🌧️ November to January (avg)  ·  up to 271 mm

☔ Heavy Rainfall expected — carry rain gear and plan outdoor activities around these months.

📅 Monthly Averages

🌡️ Temperature Patterns

Monthly averages · 1981–2025 climate normals · °F

🌡️ Sammamish Monthly Temperature Guide

Aug is the hottest month in Sammamish, with average highs reaching 89.7°F, while Dec is the coldest with lows dropping to 15.6°F.

Temperatures rise steadily from spring, peak in Aug, and gradually decline through fall into winter.

These seasonal patterns make summer pleasant for travel, while winters can bring frost and occasional snowfall.

🌧️ Rainfall Distribution

Monthly rainfall · 1981–2025 seasonal trends · mm/month

💨 Humidity & Wind Speed

Monthly averages · 1981–2025

💧 Rainfall & Humidity in Sammamish

Sammamish receives its highest rainfall in Nov, while humidity peaks during winter months.
🌧️ Wettest: Nov — 271 mm ☀️ Driest: Jul — 36 mm

💧 Humidity peaks at 92% in Dec · annual avg 84%

🌍 Climate Summary

Avg Annual Temp:50.2°F
Avg Annual Rainfall:1748 mm
Avg Humidity:84%
Data Period:1981 – 2025

Sammamish Climate Overview

Sammamish has a temperate climate with warm summers and cold winters.

Temperatures peak in Aug and drop to their lowest in Dec, while rainfall is highest during autumn months.

Humidity remains high throughout the year, especially during winter months, creating cold and damp conditions.

📈 Yearly Trends

The warmest year in Sammamish's recorded history was 2015 (avg: 53.2°F), while the coldest year was 1985 (avg: 46.8°F), based on annual average temperatures.

📊 Key Climate Trends

🌡️ Annual Temperature Trend

View Range:

Average annual high/low · Last 10 years · °F

Sammamish's temperatures has remained relatively stable over the past decade. The highest recorded temperature reached 101.8°F in Jun 2021, while the lowest dropped to -7.9°F in Feb 1989.

🌧️ Annual Precipitation

View Range:

Total annual precipitation · Last 10 years · mm/year

Annual rainfall in Sammamish shows noticeable variation. Rainfall varies year-to-year without a clear long-term trend.
📋 Yearly Climate Data Overview

🔥 hottest  ·  ❄️ coldest  ·  🌧️ wettest

Year Min Temp Avg Temp Max Temp Rainfall (mm) Avg Humidity Avg Wind

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❓ Frequently Asked Questions

What is the hottest month in Sammamish?
Based on 45 years of data (1981–2025), Aug is typically the hottest month in Sammamish, Washington, with average high temperatures around 89.7°F.
What is the coldest month in Sammamish?
Dec is the coldest month in Sammamish, with average low temperatures around 15.6°F.
What is the rainiest month in Sammamish?
Nov receives the most rainfall with approximately 271 mm, while Jul is the driest with 36 mm.
What was the highest temperature ever recorded in Sammamish?
The highest recorded temperature was 101.8°F in Jun 2021. This is part of the historical record spanning 1981–2025.
What was the lowest temperature ever recorded in Sammamish?
The lowest recorded temperature was -7.9°F in Feb 1989.
How many years of data does this page cover?
This page covers 45 years of climate data from 1981 to 2025. As new data is added to the database the page automatically reflects the updated coverage.
How much sunlight does Sammamish get?
Sammamish receives the most sunlight in Jul with an average solar radiation of 6.20 kWh/m²/day. This solar radiation data, sourced from NASA POWER, is useful for solar energy planning, agriculture, and understanding seasonal sunshine availability in Washington.
Where does this weather data come from?
All climate data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite and model data. It provides monthly averages for temperature, precipitation, humidity, wind speed, and solar radiation.

📚 Data Source

All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources), a NASA project providing solar and meteorological data for renewable energy, building efficiency, and agricultural research.

Parameters included:
  • Temperature (Min, Max)
  • Precipitation
  • Relative Humidity
  • Wind Speed
  • Solar Radiation
Data specifications:
  • Resolution: Monthly
  • Spatial: 0.5° × 0.625°
  • Source: MERRA-2
  • Coverage: 1981–2025
  • Years: 45