Rockford weather in May: Rockford, Illinois: normal highs, lows, rain and records for May
Rockford in May has a normal high of 71°F and a normal low of 50°F, a daily mean of 60°F, rising from 66°F on the 1st to 77°F by the 31st. Measurable precipitation falls on 13 days in a normal May, 4.18 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 22°C and low of 10°C, 106 mm of precipitation in May.
- NOAA stationRockford Greater Rockford Airport
- Station IDUSW00094822
- Location42.19°N 89.09°W
- Elevation730 ft (223 m)
- From the center5 miles
- Population147,486
- Jan 29° 15°
- Feb 33° 18°
- Mar 47° 28°
- Apr 60° 39°
- May 71° 50°
- Jun 81° 60°
- Jul 84° 64°
- Aug 82° 62°
- Sep 75° 54°
- Oct 62° 42°
- Nov 47° 31°
- Dec 34° 20°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Rockford in May?
The normal high is 71°F and the normal low 50°F, for a daily mean of 60.4°F. May is 11.3°F warmer than April and 9.7°F cooler than June. May is the 5th warmest month of the year in Rockford and the 3rd wettest. Across the month the normal high rises 11°F, from 66°F on May 1 to 77°F on May 31. From one year to the next May's mean temperature typically moves about 3.0°F either way (NOAA's standard deviation), so roughly two Mays in three average between 57°F and 63°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 43%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 66°F | 44°F | 42% | 25% |
| May 8 | 68°F | 47°F | 42% | 25% |
| May 15 | 71°F | 49°F | 42% | 25% |
| May 22 | 73°F | 52°F | 41% | 26% |
| May 31 | 77°F | 55°F | 40% | 26% |
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% | 25% | 14 h |
| May 2 | 66°F | 44°F | 42% | 25% | 14 h |
| May 3 | 66°F | 45°F | 42% | 25% | 14 h 10 min |
| May 4 | 67°F | 45°F | 42% | 25% | 14 h 10 min |
| May 5 | 67°F | 46°F | 42% | 25% | 14 h 10 min |
| May 6 | 68°F | 46°F | 42% | 25% | 14 h 10 min |
| May 7 | 68°F | 46°F | 42% | 25% | 14 h 20 min |
| May 8 | 68°F | 47°F | 42% | 25% | 14 h 20 min |
| May 9 | 69°F | 47°F | 43% | 25% | 14 h 20 min |
| May 10 | 69°F | 47°F | 43% | 25% | 14 h 20 min |
| May 11 | 69°F | 48°F | 42% | 25% | 14 h 20 min |
| May 12 | 70°F | 48°F | 42% | 25% | 14 h 30 min |
| May 13 | 70°F | 48°F | 42% | 25% | 14 h 30 min |
| May 14 | 71°F | 49°F | 42% | 25% | 14 h 30 min |
| May 15 | 71°F | 49°F | 42% | 25% | 14 h 30 min |
| May 16 | 71°F | 50°F | 42% | 25% | 14 h 30 min |
| May 17 | 72°F | 50°F | 42% | 25% | 14 h 40 min |
| May 18 | 72°F | 50°F | 42% | 25% | 14 h 40 min |
| May 19 | 72°F | 51°F | 42% | 26% | 14 h 40 min |
| May 20 | 73°F | 51°F | 42% | 26% | 14 h 40 min |
| May 21 | 73°F | 51°F | 42% | 26% | 14 h 40 min |
| May 22 | 73°F | 52°F | 41% | 26% | 14 h 50 min |
| May 23 | 74°F | 52°F | 41% | 26% | 14 h 50 min |
| May 24 | 74°F | 52°F | 41% | 26% | 14 h 50 min |
| May 25 | 75°F | 53°F | 41% | 26% | 14 h 50 min |
| May 26 | 75°F | 53°F | 41% | 26% | 14 h 50 min |
| May 27 | 75°F | 54°F | 41% | 26% | 14 h 50 min |
| May 28 | 76°F | 54°F | 41% | 26% | 15 h |
| May 29 | 76°F | 54°F | 41% | 26% | 15 h |
| May 30 | 76°F | 55°F | 40% | 26% | 15 h |
| May 31 | 77°F | 55°F | 40% | 26% | 15 h |
- Normal high
- 71°FMay average
- Normal low
- 50°FMay average
- Precipitation
- 4.18 inmonth total
- Days with precipitation
- 130.01 inch or more
- Days at 90°F or more
- 1
- Nights at 32°F or colder
- 1
- Daylight
- 14 h to 15 hMay 1 to May 31
- Days at 70°F or more
- 18
- Days at 80°F or more
- 7
- Sunshine
- 71%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00094822; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Rockford in May?
On a given May day the chance of 0.01 inch or more is 42% on average, highest around May 9 (43%). In all, 4.18 in falls on 13 days of a normal May, 1 of them with an inch or more.
In a normal May in Rockford, 1 days reach 90°F and 1 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00094822.
How humid and windy is Rockford in May?
At 3 p.m. the normal temperature is 74°F with 49% relative humidity and a dew point of 53°F; at 6 a.m. it is 59°F with 80% humidity. The wind averages 8.4 mph, most often from the west-southwest in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 59°F | 53°F | 80% | 6.4 mph | 25% |
| 9 a.m. | 67°F | 54°F | 63% | 9.8 mph | – |
| noon | 72°F | 54°F | 53% | 11.5 mph | 21% |
| 3 p.m. | 74°F | 53°F | 49% | 11.2 mph | 20% |
| 6 p.m. | 71°F | 53°F | 52% | 10.0 mph | 25% |
| 9 p.m. | 64°F | 53°F | 68% | 7.0 mph | 43% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00094822. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for May in Rockford?
The warmest May temperature on Rockford's official record (since 1893) is 106°F, on May 31, 1934; the coldest is 24°F, on May 10, 1966. The wettest May brought 11.75 in (1996); the snowiest, 1.5 inches (1940).
The May mean against the 1991-2020 normal of 60.4°F: 2021 60.8°F (+0.4), 2022 63.5°F (+3.1), 2023 61.5°F (+1.1), 2024 64.2°F (+3.8), 2025 59.1°F (−1.3), 2026 59.5°F (−0.9). 4 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.8°F | +0.4°F | 2.36 in |
| 2022 | 63.5°F | +3.1°F | 2.54 in |
| 2023 | 61.5°F | +1.1°F | 2.00 in |
| 2024 | 64.2°F | +3.8°F | 3.96 in |
| 2025 | 59.1°F | −1.3°F | 2.17 in |
| 2026 | 59.5°F | −0.9°F | 0.52 in |
Source: records: ACIS, NWS threaded record RFDthr; recent months: ACIS, station USW00094822. Records and recent months use complete months only.
How does May in Rockford 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; Rockford's is 71°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.