Monthly outlook for Sammamish, WA: average high 76.5°, average low 56.2°. That is 0.8° above the climate normal for August. Precipitation is expected on 5 days (about 1.5 inches), against a normal of 3 days and 0.8 inches. The warmest day looks like 15 August (86°), the coolest 10 August (52.1°).
76.5°/56.2°
Average high / low
+0.8°
Above normal
5 / 3
Wet days / normal
1.5 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
9 August – 18 August
79.8°
76°
+2.1°
19 August – 28 August
71.1°
73.5°
-1.4°
29 August – 7 September
at normal
71.5°
—
August records over 66 years
95.9°9 August 1981All-time high
43°30 August 1965All-time low
Climate normals and records are computed from the nearest reference point — Bellevue (5 mi).
Mon, 1078° / 52°0
78 °
Sammamish, Monday, 10 August
Overcast. High 78°, low 52°.
Pressure30.06 inHg
Wind3.2 mph W
Humidity44%
Visibility6.2 mi
Dew point51°
Tue, 1182° / 52°0
82 °
Sammamish, Tuesday, 11 August
Clear. High 82°, low 52°.
Pressure30.09 inHg
Wind3.9 mph N
Humidity37%
Visibility6.2 mi
Dew point49°
Wed, 1281° / 54°0
81 °
Sammamish, Wednesday, 12 August
Clear. High 81°, low 54°.
Pressure29.97 inHg
Wind3.5 mph NW
Humidity42%
Visibility6.2 mi
Dew point51°
Thu, 1384° / 55°0
84 °
Sammamish, Thursday, 13 August
Clear. High 84°, low 55°.
Pressure29.85 inHg
Wind8.9 mph NW
Humidity34%
Visibility—
Dew point49°
Fri, 1485° / 56°0
85 °
Sammamish, Friday, 14 August
Overcast. High 85°, low 56°.
Pressure29.91 inHg
Wind6.3 mph NW
Humidity35%
Visibility—
Dew point51°
Sat, 1586° / 57°0
86 °
Sammamish, Saturday, 15 August
Overcast. High 86°, low 57°.
Pressure29.94 inHg
Wind4.7 mph NW
Humidity32%
Visibility—
Dew point48°
Sun, 1683° / 55°0
83 °
Sammamish, Sunday, 16 August
Overcast. High 83°, low 55°.
Pressure29.94 inHg
Wind5.7 mph S
Humidity30%
Visibility—
Dew point45°
Mon, 1762° / 58°0.37
62 °
Sammamish, Monday, 17 August
Rain. High 62°, low 58°.
Pressure30.00 inHg
Wind6.2 mph SW
Humidity94%
Visibility—
Dew point59°
Tue, 1878° / 56°0
78 °
Sammamish, Tuesday, 18 August
Partly cloudy. High 78°, low 56°.
Pressure29.97 inHg
Wind5.3 mph N
Humidity40%
Visibility—
Dew point49°
Wed, 1978° / 57°0
78 °
Sammamish, Wednesday, 19 August
Overcast. High 78°, low 57°.
Pressure29.97 inHg
Wind5.2 mph S
Humidity42%
Visibility—
Dew point51°
Thu, 2082° / 61°0.09
82 °
Sammamish, Thursday, 20 August
Light rain. High 82°, low 61°.
Pressure29.88 inHg
Wind5.8 mph W
Humidity44%
Visibility—
Dew point56°
Fri, 2172° / 60°0.07
72 °
Sammamish, Friday, 21 August
Light rain. High 72°, low 60°.
Pressure29.94 inHg
Wind7.5 mph SW
Humidity51%
Visibility—
Dew point51°
Sat, 2265° / 59°0.4
65 °
Sammamish, Saturday, 22 August
Light rain. High 65°, low 59°.
Pressure30.03 inHg
Wind3.9 mph S
Humidity97%
Visibility—
Dew point59°
Sun, 2371° / 56°0
71 °
Sammamish, Sunday, 23 August
Overcast. High 71°, low 56°.
Pressure30.09 inHg
Wind4.8 mph S
Humidity56%
Visibility—
Dew point52°
Mon, 2459° / 54°0.59
59 °
Sammamish, Monday, 24 August
Rain. High 59°, low 54°.
Pressure29.88 inHg
Wind4.9 mph SE
Humidity96%
Visibility—
Dew point56°
From day 17 onward the outlook is built from 60-year climate statistics
Tue, 2573° / 54°0.07
73 °
Sammamish, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high73°
Average low54°
Average precipitation0.07 in
Chance of precipitation18%
Record high87° (2025)
Record low46° (1995)
Wed, 2674° / 54°0.05
74 °
Sammamish, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high74°
Average low54°
Average precipitation0.05 in
Chance of precipitation22%
Record high88° (1986)
Record low46° (1993)
Thu, 2774° / 55°0.08
74 °
Sammamish, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high74°
Average low55°
Average precipitation0.08 in
Chance of precipitation27%
Record high90° (1986)
Record low48° (1962)
Fri, 2874° / 55°0.04
74 °
Sammamish, Friday, 28 August
Climate normal for this date — 60-year average.
Average high74°
Average low55°
Average precipitation0.04 in
Chance of precipitation20%
Record high91° (1967)
Record low45° (2000)
Sat, 2973° / 55°0.11
73 °
Sammamish, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high73°
Average low55°
Average precipitation0.11 in
Chance of precipitation25%
Record high87° (2017)
Record low44° (1980)
Sun, 3072° / 55°0.07
72 °
Sammamish, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high72°
Average low55°
Average precipitation0.07 in
Chance of precipitation33%
Record high86° (1967)
Record low43° (1965)
Mon, 3171° / 54°0.06
71 °
Sammamish, Monday, 31 August
Climate normal for this date — 60-year average.
Average high71°
Average low54°
Average precipitation0.06 in
Chance of precipitation30%
Record high91° (1987)
Record low45° (1964)
Tue, 0171° / 54°0.08
71 °
Sammamish, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high71°
Average low54°
Average precipitation0.08 in
Chance of precipitation27%
Record high87° (1987)
Record low43° (1973)
Wed, 0272° / 53°0.08
72 °
Sammamish, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high72°
Average low53°
Average precipitation0.08 in
Chance of precipitation30%
Record high93° (1988)
Record low43° (1960)
Thu, 0372° / 54°0.08
72 °
Sammamish, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high72°
Average low54°
Average precipitation0.08 in
Chance of precipitation25%
Record high92° (1988)
Record low44° (1975)
Fri, 0472° / 54°0.06
72 °
Sammamish, Friday, 4 September
Climate normal for this date — 60-year average.
Average high72°
Average low54°
Average precipitation0.06 in
Chance of precipitation22%
Record high87° (2017)
Record low44° (1965)
Sat, 0571° / 54°0.07
71 °
Sammamish, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high71°
Average low54°
Average precipitation0.07 in
Chance of precipitation30%
Record high93° (2017)
Record low46° (2000)
Sun, 0671° / 53°0.1
71 °
Sammamish, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high71°
Average low53°
Average precipitation0.1 in
Chance of precipitation28%
Record high89° (2017)
Record low42° (1960)
Mon, 0771° / 53°0.06
71 °
Sammamish, Monday, 7 September
Climate normal for this date — 60-year average.
Average high71°
Average low53°
Average precipitation0.06 in
Chance of precipitation28%
Record high88° (1981)
Record low42° (1960)
About the monthly outlook
How accurate is a 30-day forecast?
The first 16 days come from weather models — reliable for the first 3–5 days and progressively less so after that. Days 17 through 30 for Sammamish, WA are built from the climate normal, the 60-year average, so they show typical weather for those dates rather than a specific forecast.
What does "above normal" mean?
We compare the forecast against the climate normal for those exact calendar days, computed from 60 years of observations. The deviation shows how much the coming month differs from a typical one.
Where do the 66-year records come from?
They are real temperature extremes recorded in Sammamish, WA since 1960: the highest and lowest reading for each calendar date, with the year it happened.
How often is it updated?
The forecast portion refreshes every hour; the climate portion is based on long-term data and stays stable.