Joliet weather in May: Joliet, Illinois: normal highs, lows, rain and records for May
Joliet in May has a normal high of 71°F and a normal low of 49°F, a daily mean of 60°F, rising from 66°F on the 1st to 76°F by the 31st. Measurable precipitation falls on 12 days in a normal May, 4.53 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 22°C and low of 10°C, 115 mm of precipitation in May.
- 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 May?
The normal high is 71°F and the normal low 49°F, for a daily mean of 60.2°F. May is 10.8°F warmer than April and 9.9°F cooler than June. May is the 5th warmest month of the year in Joliet and the 2nd wettest. Across the month the normal high rises 10°F, from 66°F on May 1 to 76°F on May 31. From one year to the next May's mean temperature typically moves about 3.4°F either way (NOAA's standard deviation), so roughly two Mays in three average between 57°F and 64°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 42%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 66°F | 44°F | 42% | 26% |
| May 8 | 68°F | 47°F | 41% | 26% |
| May 15 | 71°F | 49°F | 41% | 26% |
| May 22 | 73°F | 52°F | 40% | 26% |
| May 31 | 76°F | 55°F | 38% | 25% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 66°F | 44°F | 42% | 26% | 14 h |
| May 2 | 66°F | 45°F | 42% | 26% | 14 h |
| May 3 | 67°F | 45°F | 42% | 26% | 14 h |
| May 4 | 67°F | 45°F | 42% | 26% | 14 h 10 min |
| May 5 | 67°F | 46°F | 42% | 26% | 14 h 10 min |
| May 6 | 68°F | 46°F | 41% | 26% | 14 h 10 min |
| May 7 | 68°F | 46°F | 41% | 26% | 14 h 10 min |
| May 8 | 68°F | 47°F | 41% | 26% | 14 h 10 min |
| May 9 | 69°F | 47°F | 41% | 27% | 14 h 20 min |
| May 10 | 69°F | 47°F | 41% | 27% | 14 h 20 min |
| May 11 | 69°F | 48°F | 41% | 27% | 14 h 20 min |
| May 12 | 70°F | 48°F | 41% | 27% | 14 h 20 min |
| May 13 | 70°F | 48°F | 41% | 27% | 14 h 20 min |
| May 14 | 70°F | 49°F | 41% | 26% | 14 h 30 min |
| May 15 | 71°F | 49°F | 41% | 26% | 14 h 30 min |
| May 16 | 71°F | 49°F | 41% | 26% | 14 h 30 min |
| May 17 | 71°F | 50°F | 40% | 26% | 14 h 30 min |
| May 18 | 72°F | 50°F | 40% | 26% | 14 h 30 min |
| May 19 | 72°F | 50°F | 40% | 26% | 14 h 40 min |
| May 20 | 72°F | 51°F | 40% | 26% | 14 h 40 min |
| May 21 | 73°F | 51°F | 40% | 26% | 14 h 40 min |
| May 22 | 73°F | 52°F | 40% | 26% | 14 h 40 min |
| May 23 | 73°F | 52°F | 40% | 26% | 14 h 40 min |
| May 24 | 74°F | 52°F | 40% | 26% | 14 h 50 min |
| May 25 | 74°F | 53°F | 39% | 26% | 14 h 50 min |
| May 26 | 74°F | 53°F | 39% | 26% | 14 h 50 min |
| May 27 | 75°F | 53°F | 39% | 25% | 14 h 50 min |
| May 28 | 75°F | 54°F | 39% | 25% | 14 h 50 min |
| May 29 | 75°F | 54°F | 39% | 25% | 14 h 50 min |
| May 30 | 76°F | 54°F | 39% | 25% | 14 h 50 min |
| May 31 | 76°F | 55°F | 38% | 25% | 15 h |
- Normal high
- 71°FMay average
- Normal low
- 49°FMay average
- Precipitation
- 4.53 inmonth total
- Days with precipitation
- 120.01 inch or more
- Days at 90°F or more
- 1
- Daylight
- 14 h to 15 hMay 1 to May 31
- Days at 70°F or more
- 18
- Days at 80°F or more
- 8
- Sunshine
- 71%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 May?
On a given May day the chance of 0.01 inch or more is 40% on average, highest around May 1 (42%). In all, 4.53 in falls on 12 days of a normal May, 1 of them with an inch or more.
In a normal May in Joliet, 1 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00114530.
What are the records for May in Joliet?
The warmest May temperature on this station's record (since 1975) is 95°F, on May 28, 2012; the coldest is 28°F, on May 10, 2020. The wettest May brought 7.97 in (2019).
The May mean against the 1991-2020 normal of 60.2°F: 2021 58.0°F (−2.2), 2022 61.5°F (+1.3), 2023 61.0°F (+0.8), 2024 63.4°F (+3.2), 2025 58.8°F (−1.4), 2026 60.0°F (−0.2). 3 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 58.0°F | −2.2°F | 3.69 in |
| 2022 | 61.5°F | +1.3°F | 4.53 in |
| 2023 | 61.0°F | +0.8°F | 1.83 in |
| 2024 | 63.4°F | +3.2°F | 7.19 in |
| 2025 | 58.8°F | −1.4°F | 1.19 in |
| 2026 | 60.0°F | −0.2°F | 1.55 in |
Source: records: ACIS, station USC00114530; recent months: ACIS, station USC00114530. Records and recent months use complete months only.
How does May in Joliet compare across Illinois?
Across the 144 places PlainClimate covers in Illinois, May normal highs run from 67°F in Waukegan to 79°F in Belleville; Joliet's is 71°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.