Monthly outlook for Holtsville, NY: average high 81.3°, average low 70°. That is 2° above the climate normal for August. Precipitation is expected on 4 days (about 1.7 inches), against a normal of 5 days and 2.2 inches. The warmest day looks like 9 August (90.3°), the coolest 22 August (64.8°).
81.3°/70°
Average high / low
+2°
Above normal
4 / 5
Wet days / normal
1.7 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
9 August – 18 August
82.6°
78.3°
+2.4°
19 August – 28 August
79.3°
76.8°
+1.4°
29 August – 7 September
at normal
75.5°
—
August records over 66 years
92.3°2 August 1975All-time high
52.2°29 August 1982All-time low
Climate normals and records are computed from the nearest reference point — Brookhaven (5 mi).
Mon, 1089° / 73°0.02
89 °
Holtsville, Monday, 10 August
Light rain. High 89°, low 73°.
Pressure29.97 inHg
Wind6 mph S
Humidity48%
Visibility6.2 mi
Dew point61°
Tue, 1189° / 77°0
89 °
Holtsville, Tuesday, 11 August
Overcast. High 89°, low 77°.
Pressure29.85 inHg
Wind10.3 mph NW
Humidity41%
Visibility6.2 mi
Dew point59°
Wed, 1279° / 71°0.11
79 °
Holtsville, Wednesday, 12 August
Light rain. High 79°, low 71°.
Pressure29.71 inHg
Wind2.4 mph NW
Humidity80%
Visibility6.2 mi
Dew point68°
Thu, 1385° / 71°0.16
85 °
Holtsville, Thursday, 13 August
Light rain. High 85°, low 71°.
Pressure29.71 inHg
Wind16.2 mph NW
Humidity54%
Visibility—
Dew point61°
Fri, 1479° / 66°0
79 °
Holtsville, Friday, 14 August
Clear. High 79°, low 66°.
Pressure30.00 inHg
Wind11.2 mph NW
Humidity40%
Visibility—
Dew point46°
Sat, 1581° / 67°0
81 °
Holtsville, Saturday, 15 August
Clear. High 81°, low 67°.
Pressure30.09 inHg
Wind14 mph NW
Humidity42%
Visibility—
Dew point48°
Sun, 1679° / 66°0
79 °
Holtsville, Sunday, 16 August
Overcast. High 79°, low 66°.
Pressure30.18 inHg
Wind10.3 mph N
Humidity35%
Visibility—
Dew point44°
Mon, 1778° / 71°0
78 °
Holtsville, Monday, 17 August
Overcast. High 78°, low 71°.
Pressure30.18 inHg
Wind13.5 mph S
Humidity53%
Visibility—
Dew point58°
Tue, 1877° / 68°0.09
77 °
Holtsville, Tuesday, 18 August
Light rain. High 77°, low 68°.
Pressure30.15 inHg
Wind9.5 mph SW
Humidity69%
Visibility—
Dew point61°
Wed, 1978° / 70°0
78 °
Holtsville, Wednesday, 19 August
Overcast. High 78°, low 70°.
Pressure30.00 inHg
Wind13.1 mph S
Humidity60%
Visibility—
Dew point58°
Thu, 2080° / 67°1.31
80 °
Holtsville, Thursday, 20 August
Heavy rain. High 80°, low 67°.
Pressure29.65 inHg
Wind17.3 mph NW
Humidity83%
Visibility—
Dew point67°
Fri, 2177° / 67°0
77 °
Holtsville, Friday, 21 August
Overcast. High 77°, low 67°.
Pressure29.80 inHg
Wind15.4 mph W
Humidity59%
Visibility—
Dew point54°
Sat, 2278° / 65°0
78 °
Holtsville, Saturday, 22 August
Clear. High 78°, low 65°.
Pressure30.03 inHg
Wind10.8 mph NW
Humidity35%
Visibility—
Dew point42°
Sun, 2377° / 71°0
77 °
Holtsville, Sunday, 23 August
Overcast. High 77°, low 71°.
Pressure30.09 inHg
Wind18.2 mph S
Humidity55%
Visibility—
Dew point58°
Mon, 2485° / 75°0
85 °
Holtsville, Monday, 24 August
Clear. High 85°, low 75°.
Pressure29.85 inHg
Wind17.2 mph SW
Humidity55%
Visibility—
Dew point64°
From day 17 onward the outlook is built from 60-year climate statistics
Tue, 2577° / 67°0.09
77 °
Holtsville, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high77°
Average low67°
Average precipitation0.09 in
Chance of precipitation28%
Record high89° (2020)
Record low58° (1963)
Wed, 2677° / 67°0.09
77 °
Holtsville, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high77°
Average low67°
Average precipitation0.09 in
Chance of precipitation25%
Record high87° (2021)
Record low60° (1963)
Thu, 2778° / 68°0.12
78 °
Holtsville, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high78°
Average low68°
Average precipitation0.12 in
Chance of precipitation28%
Record high90° (2020)
Record low59° (1969)
Fri, 2877° / 68°0.18
77 °
Holtsville, Friday, 28 August
Climate normal for this date — 60-year average.
Average high77°
Average low68°
Average precipitation0.18 in
Chance of precipitation35%
Record high87° (2024)
Record low57° (1986)
Sat, 2976° / 68°0.15
76 °
Holtsville, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high76°
Average low68°
Average precipitation0.15 in
Chance of precipitation30%
Record high86° (2018)
Record low52° (1982)
Sun, 3077° / 67°0.07
77 °
Holtsville, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high77°
Average low67°
Average precipitation0.07 in
Chance of precipitation27%
Record high88° (2018)
Record low55° (1965)
Mon, 3177° / 67°0.04
77 °
Holtsville, Monday, 31 August
Climate normal for this date — 60-year average.
Average high77°
Average low67°
Average precipitation0.04 in
Chance of precipitation18%
Record high89° (2010)
Record low56° (1976)
Tue, 0175° / 67°0.06
75 °
Holtsville, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high75°
Average low67°
Average precipitation0.06 in
Chance of precipitation25%
Record high87° (2010)
Record low55° (2017)
Wed, 0275° / 66°0.2
75 °
Holtsville, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high75°
Average low66°
Average precipitation0.2 in
Chance of precipitation28%
Record high87° (1966)
Record low56° (2017)
Thu, 0375° / 66°0.11
75 °
Holtsville, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high75°
Average low66°
Average precipitation0.11 in
Chance of precipitation30%
Record high84° (1973)
Record low54° (2025)
Fri, 0476° / 66°0.13
76 °
Holtsville, Friday, 4 September
Climate normal for this date — 60-year average.
Average high76°
Average low66°
Average precipitation0.13 in
Chance of precipitation22%
Record high87° (2018)
Record low56° (1997)
Sat, 0575° / 66°0.05
75 °
Holtsville, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high75°
Average low66°
Average precipitation0.05 in
Chance of precipitation18%
Record high90° (2023)
Record low56° (2000)
Sun, 0674° / 66°0.14
74 °
Holtsville, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high74°
Average low66°
Average precipitation0.14 in
Chance of precipitation33%
Record high90° (2023)
Record low56° (1962)
Mon, 0775° / 65°0.1
75 °
Holtsville, Monday, 7 September
Climate normal for this date — 60-year average.
Average high75°
Average low65°
Average precipitation0.1 in
Chance of precipitation32%
Record high90° (2023)
Record low56° (1984)
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 Holtsville, NY 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 Holtsville, NY 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.