Monthly outlook for St. Marys, KS: average high 101.7°, average low 74.6°. That is 8.1° above the climate normal for August. Precipitation is expected on 7 days (about 0.9 inches), against a normal of 5 days and 1.8 inches. The warmest day looks like 20 August (117.2°), the coolest 14 August (66.8°).
101.7°/74.6°
Average high / low
+8.1°
Above normal
7 / 5
Wet days / normal
0.9 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
9 August – 18 August
96°
87°
+5°
19 August – 28 August
111.1°
87°
+13.4°
29 August – 7 September
at normal
84.5°
—
August records over 66 years
106.9°19 August 2023All-time high
51.3°31 August 2009All-time low
Climate normals and records are computed from the nearest reference point — Rossville (7 mi).
Mon, 10100° / 76°0.01
100 °
St. Marys, Monday, 10 August
Light rain. High 100°, low 76°.
Pressure29.85 inHg
Wind6 mph SW
Humidity36%
Visibility6.2 mi
Dew point63°
Tue, 11109° / 74°0.18
109 °
St. Marys, Tuesday, 11 August
Rain. High 109°, low 74°.
Pressure29.74 inHg
Wind17.9 mph SW
Humidity30%
Visibility6.2 mi
Dew point62°
Wed, 1293° / 75°0.02
93 °
St. Marys, Wednesday, 12 August
Light rain. High 93°, low 75°.
Pressure29.77 inHg
Wind6.1 mph N
Humidity40%
Visibility6.2 mi
Dew point64°
Thu, 1397° / 73°0.09
97 °
St. Marys, Thursday, 13 August
Light rain. High 97°, low 73°.
Pressure29.77 inHg
Wind28.7 mph NE
Humidity46%
Visibility—
Dew point65°
Fri, 1486° / 67°0.08
86 °
St. Marys, Friday, 14 August
Light rain. High 86°, low 67°.
Pressure29.94 inHg
Wind17.8 mph NE
Humidity68%
Visibility—
Dew point66°
Sat, 1587° / 67°0.07
87 °
St. Marys, Saturday, 15 August
Light rain. High 87°, low 67°.
Pressure30.06 inHg
Wind14.9 mph NE
Humidity69%
Visibility—
Dew point67°
Sun, 1692° / 69°0.01
92 °
St. Marys, Sunday, 16 August
Light rain. High 92°, low 69°.
Pressure30.09 inHg
Wind9.8 mph NE
Humidity52%
Visibility—
Dew point65°
Mon, 1784° / 71°0.07
84 °
St. Marys, Monday, 17 August
Light rain. High 84°, low 71°.
Pressure30.03 inHg
Wind15.8 mph SE
Humidity77%
Visibility—
Dew point69°
Tue, 18113° / 71°0
113 °
St. Marys, Tuesday, 18 August
Overcast. High 113°, low 71°.
Pressure29.80 inHg
Wind15.1 mph SW
Humidity15%
Visibility—
Dew point46°
Wed, 19115° / 81°0
115 °
St. Marys, Wednesday, 19 August
Clear. High 115°, low 81°.
Pressure29.74 inHg
Wind19.2 mph SW
Humidity11%
Visibility—
Dew point43°
Thu, 20117° / 83°0
117 °
St. Marys, Thursday, 20 August
Clear. High 117°, low 83°.
Pressure29.74 inHg
Wind16.2 mph SW
Humidity10%
Visibility—
Dew point41°
Fri, 21113° / 77°0
113 °
St. Marys, Friday, 21 August
Mostly clear. High 113°, low 77°.
Pressure29.83 inHg
Wind8.7 mph E
Humidity20%
Visibility—
Dew point51°
Sat, 22113° / 85°0.01
113 °
St. Marys, Saturday, 22 August
Light rain. High 113°, low 85°.
Pressure29.74 inHg
Wind21.9 mph SW
Humidity15%
Visibility—
Dew point51°
Sun, 23107° / 75°0.14
107 °
St. Marys, Sunday, 23 August
Light rain. High 107°, low 75°.
Pressure29.80 inHg
Wind13.2 mph SW
Humidity23%
Visibility—
Dew point55°
Mon, 24102° / 73°0.16
102 °
St. Marys, Monday, 24 August
Light rain. High 102°, low 73°.
Pressure29.91 inHg
Wind12 mph SE
Humidity36%
Visibility—
Dew point62°
From day 17 onward the outlook is built from 60-year climate statistics
Tue, 2587° / 69°0.16
87 °
St. Marys, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high87°
Average low69°
Average precipitation0.16 in
Chance of precipitation27%
Record high104° (2023)
Record low57° (2010)
Wed, 2687° / 69°0.13
87 °
St. Marys, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high87°
Average low69°
Average precipitation0.13 in
Chance of precipitation32%
Record high99° (1983)
Record low55° (1985)
Thu, 2787° / 69°0.06
87 °
St. Marys, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high87°
Average low69°
Average precipitation0.06 in
Chance of precipitation22%
Record high100° (2000)
Record low56° (1967)
Fri, 2887° / 68°0.11
87 °
St. Marys, Friday, 28 August
Climate normal for this date — 60-year average.
Average high87°
Average low68°
Average precipitation0.11 in
Chance of precipitation25%
Record high103° (1984)
Record low54° (1992)
Sat, 2986° / 68°0.11
86 °
St. Marys, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high86°
Average low68°
Average precipitation0.11 in
Chance of precipitation27%
Record high102° (1984)
Record low53° (1974)
Sun, 3085° / 68°0.12
85 °
St. Marys, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high85°
Average low68°
Average precipitation0.12 in
Chance of precipitation37%
Record high99° (2013)
Record low54° (2009)
Mon, 3185° / 68°0.18
85 °
St. Marys, Monday, 31 August
Climate normal for this date — 60-year average.
Average high85°
Average low68°
Average precipitation0.18 in
Chance of precipitation35%
Record high101° (2000)
Record low51° (2009)
Tue, 0184° / 67°0.16
84 °
St. Marys, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high84°
Average low67°
Average precipitation0.16 in
Chance of precipitation30%
Record high103° (2011)
Record low54° (1965)
Wed, 0284° / 67°0.1
84 °
St. Marys, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high84°
Average low67°
Average precipitation0.1 in
Chance of precipitation30%
Record high102° (2000)
Record low51° (1974)
Thu, 0385° / 67°0.08
85 °
St. Marys, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high85°
Average low67°
Average precipitation0.08 in
Chance of precipitation22%
Record high100° (2000)
Record low46° (1974)
Fri, 0484° / 66°0.09
84 °
St. Marys, Friday, 4 September
Climate normal for this date — 60-year average.
Average high84°
Average low66°
Average precipitation0.09 in
Chance of precipitation27%
Record high96° (2023)
Record low45° (1974)
Sat, 0584° / 66°0.07
84 °
St. Marys, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high84°
Average low66°
Average precipitation0.07 in
Chance of precipitation20%
Record high98° (1990)
Record low46° (1974)
Sun, 0684° / 65°0.09
84 °
St. Marys, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high84°
Average low65°
Average precipitation0.09 in
Chance of precipitation22%
Record high99° (1990)
Record low50° (2025)
Mon, 0783° / 66°0.12
83 °
St. Marys, Monday, 7 September
Climate normal for this date — 60-year average.
Average high83°
Average low66°
Average precipitation0.12 in
Chance of precipitation25%
Record high99° (2013)
Record low53° (2025)
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 St. Marys, KS 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 St. Marys, KS 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.