Joliet, IL weather in May
In May, Joliet sees highs around 71°F and lows around 49°F: mild, with frequent rain. Rain falls on about 12 days.
- Normal high
- 71°F
- Normal low
- 49°F
- Wet days
- 12
- 4.5 in total
- Muggy days
- 1
- dew point 65°F+
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 66°F | 76°F |
| Normal low | 44°F | 55°F |
| Chance of a wet day | 42% | 39% |
| Sunrise / sunset | 5:49 am / 7:49 pm | 5:21 am / 8:18 pm |
| Daylight | 14.0 h | 15.0 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Central Time).
A typical May day
- 6 am56°Fdew point 48°F
- 9 am62°Fdew point 48°F
- Noon66°Fdew point 48°F
- 3 pm68°Fdew point 48°F
- 6 pm64°Fdew point 47°F
- 9 pm60°Fdew point 47°F
NOAA hourly normals (local standard time) from Chicago Midway Airport (25 mi away); average wind 10 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F15 of 31
- Hot dayshigh 90°F or more1 of 31
- Muggy daysdaily mean dew point 65°F or more1 of 31
- Wet daysat least 0.01 in of rain or melted snow12 of 31
- Notable rainat least 0.10 in8 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per May, counted from daily records for each year 1991-2020.
Rain in May
Normal precipitation is 4.5 in; a dry May brings about 3.6 in and a wet one about 5.2 in (25th and 75th percentiles). About 3 days bring half an inch or more, and about 1 an inch or more.
How May varies from year to year
- Warmest May, 1991-20202018: average high 78°F
- Coolest May2002: average high 65°F
- Wettest May2019: 8.0 in
- Driest May1992: 0.7 in
- Highest reading95°F (May 28, 2018)
- Lowest reading28°F (May 10, 2020)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
May compared with April and June
| April | May | June | |
|---|---|---|---|
| Normal high | 60°F | 71°F | 80°F |
| Normal low | 39°F | 49°F | 60°F |
| Wet days | 12 | 12 | 11 |
| Comfortable days | 10 | 15 | 10 |
| Daylight | 13.3 h | 14.5 h | 15.1 h |
Highs change by +11°F from April and +9°F into June.
Nearby alternatives in May
- Warmer: St. Louis, MO229 mi · high 77°F · 13 wet days
How Joliet ranks in May
- Normal high252nd warmest of 378 cities; 7th of 8 in Illinois
- Wet days290th driest of 378
- Comfortable days90th most of 339
What to pack for Joliet in May
- A rain jacket or umbrella – rain on about 12 days
Heating and cooling
May has 203 heating degree days and 54 cooling degree days (base 65°F), 4% of the year's total heating and cooling demand.
Questions
How hot is Joliet in May?
The normal high is 71°F and the normal low is 49°F. From 1991 to 2020 the hottest May reading was 95°F (most recently on May 28, 2018).
Does it rain a lot in Joliet in May?
About 12 days in May have at least 0.01 in of precipitation, and the normal total is 4.5 in. The wettest May in 1991-2020 was in 2019 (8.0 in); the driest was in 1992 (0.7 in).
Is May a good time to visit Joliet?
May ranks 1st of 12 months on our comfort score for Joliet (71 out of 100). It has about 15 comfortable days and about 1 day at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth and frost dates: Joliet Brandon Rd Dam (USC00114530), 1.9 mi SW of the city center, 543 ft . NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour: Chicago Midway Airport (USW00014819), 25 mi NE of the city center, 612 ft (71 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Chicago Midway Intl Arpt (725340-14819), 25 mi NE of the city center, 610 ft (69 ft higher than the city). Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).