Joliet weather in August: Joliet, Illinois: normal highs, lows, rain and records for August
Joliet in August has a normal high of 82°F and a normal low of 63°F, a daily mean of 72°F, falling from 83°F on the 1st to 80°F by the 31st. Measurable precipitation falls on 9 days in a normal August, 3.97 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 28°C and low of 17°C, 101 mm of precipitation in August.
- NOAA stationJoliet Brandon Rd Dam
- Station IDUSC00114530
- Location41.50°N 88.10°W
- Elevation543 ft (166 m)
- Population151,837
- Jan 31° 17°
- Feb 35° 20°
- Mar 47° 29°
- Apr 60° 39°
- May 71° 49°
- Jun 80° 60°
- Jul 84° 64°
- Aug 82° 63°
- Sep 76° 55°
- Oct 63° 43°
- Nov 49° 32°
- Dec 36° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Joliet in August?
The normal high is 82°F and the normal low 63°F, for a daily mean of 72.3°F. August is 1.6°F cooler than July and 6.6°F warmer than September. August is the 2nd warmest month of the year in Joliet and the 4th wettest. Across the month the normal high falls 3°F, from 83°F on August 1 to 80°F on August 31. From one year to the next August's mean temperature typically moves about 2.5°F either way (NOAA's standard deviation), so roughly two Augusts in three average between 70°F and 75°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 30%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| August 1 | 83°F | 64°F | 30% | 21% |
| August 8 | 82°F | 64°F | 30% | 21% |
| August 15 | 82°F | 63°F | 29% | 20% |
| August 22 | 81°F | 63°F | 29% | 19% |
| August 31 | 80°F | 61°F | 28% | 19% |
Every day of August: normal high, low and chance of precipitation (warmest afternoon August 1, coldest night August 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| August 1 | 83°F | 64°F | 30% | 21% | 14 h 30 min |
| August 2 | 83°F | 64°F | 30% | 21% | 14 h 20 min |
| August 3 | 83°F | 64°F | 30% | 21% | 14 h 20 min |
| August 4 | 83°F | 64°F | 30% | 21% | 14 h 20 min |
| August 5 | 83°F | 64°F | 30% | 21% | 14 h 20 min |
| August 6 | 83°F | 64°F | 30% | 21% | 14 h 10 min |
| August 7 | 83°F | 64°F | 30% | 21% | 14 h 10 min |
| August 8 | 82°F | 64°F | 30% | 21% | 14 h 10 min |
| August 9 | 82°F | 64°F | 30% | 21% | 14 h 10 min |
| August 10 | 82°F | 64°F | 30% | 20% | 14 h 10 min |
| August 11 | 82°F | 64°F | 30% | 20% | 14 h |
| August 12 | 82°F | 64°F | 29% | 20% | 14 h |
| August 13 | 82°F | 63°F | 29% | 20% | 14 h |
| August 14 | 82°F | 63°F | 29% | 20% | 14 h |
| August 15 | 82°F | 63°F | 29% | 20% | 13 h 50 min |
| August 16 | 82°F | 63°F | 29% | 20% | 13 h 50 min |
| August 17 | 82°F | 63°F | 29% | 20% | 13 h 50 min |
| August 18 | 82°F | 63°F | 29% | 20% | 13 h 50 min |
| August 19 | 82°F | 63°F | 29% | 20% | 13 h 40 min |
| August 20 | 82°F | 63°F | 29% | 20% | 13 h 40 min |
| August 21 | 82°F | 63°F | 29% | 20% | 13 h 40 min |
| August 22 | 81°F | 63°F | 29% | 19% | 13 h 40 min |
| August 23 | 81°F | 62°F | 28% | 19% | 13 h 30 min |
| August 24 | 81°F | 62°F | 28% | 19% | 13 h 30 min |
| August 25 | 81°F | 62°F | 28% | 19% | 13 h 30 min |
| August 26 | 81°F | 62°F | 28% | 19% | 13 h 30 min |
| August 27 | 81°F | 62°F | 28% | 19% | 13 h 20 min |
| August 28 | 81°F | 62°F | 28% | 19% | 13 h 20 min |
| August 29 | 81°F | 61°F | 28% | 19% | 13 h 20 min |
| August 30 | 81°F | 61°F | 28% | 19% | 13 h 20 min |
| August 31 | 80°F | 61°F | 28% | 19% | 13 h 10 min |
- Normal high
- 82°FAugust average
- Normal low
- 63°FAugust average
- Precipitation
- 3.97 inmonth total
- Days with precipitation
- 90.01 inch or more
- Days at 90°F or more
- 3
- Daylight
- 14 h 30 min to 13 h 10 minAugust 1 to August 31
- Days at 70°F or more
- 30
- Days at 80°F or more
- 22
- Sunshine
- 80%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00114530; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Joliet in August?
On a given August day the chance of 0.01 inch or more is 29% on average, highest around August 1 (30%). In all, 3.97 in falls on 9 days of a normal August, 1 of them with an inch or more.
In a normal August in Joliet, 3 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00114530.
What are the records for August in Joliet?
The warmest August temperature on this station's record (since 1975) is 102°F, on August 2, 1988; the coldest is 39°F, on August 29, 1986. The wettest August brought 10.75 in (2007).
The August mean against the 1991-2020 normal of 72.3°F: 2022 72.1°F (−0.2), 2023 71.6°F (−0.7), 2024 72.2°F (−0.1), 2025 72.5°F (+0.2), 2026 72.3°F (at normal). 1 of 5 ran warmer than normal.
| August | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 72.1°F | −0.2°F | 4.14 in |
| 2023 | 71.6°F | −0.7°F | 2.91 in |
| 2024 | 72.2°F | −0.1°F | 2.94 in |
| 2025 | 72.5°F | +0.2°F | 5.65 in |
| 2026 | 72.3°F | at normal | 6.24 in |
Source: records: ACIS, station USC00114530; recent months: ACIS, station USC00114530. Records and recent months use complete months only.
How does August in Joliet compare across Illinois?
Across the 144 places PlainClimate covers in Illinois, August normal highs run from 79°F in Barrington to 89°F in Anna; Joliet's is 82°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.