Romulus climate — normals and trends
Romulus (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 9.4 °C and it receives 872 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (22.5 °C on average) and the coldest is January (-4.3 °C). Rainfall peaks in May.
Romulus averages 123 frost days, 21 hot days (≥ 30 °C) and 120 rainy days per year.
Romulus has warmed by +1.9 °C between 1940 and 2025, or +0.22 °C per decade. This trend is statistically significant.
The number of frost days there went from about 137 to 109 per year over the period.
The hottest day of the period reached 39.9 °C (on 25 June 1988) and the coldest -29.0 °C (on 20 February 2015).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
RomulusMichigan
- coords
- 42.22°, -83.40°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.4°C
Average daily high
14.2°C
Average daily low
4.8°C
Annual rainfall
872mm
Sunshine / day
8.7h
Mean relative humidity
71%
Average peak wind
18.5km/h
Seasonal range
26.8°C
Frost days (< 0 °C)
123 d/yr
Hot days (≥ 30 °C)
21 d/yr
Rainy days (≥ 1 mm)
120 d/yr
Annual snowfall
76.5 cm
Average feels-like high
12.0 °C
Average feels-like low
1.9 °C
Average peak gust
38.8 km/h
Tropical nights (≥ 20 °C)
19 d/yr
Solar radiation
14.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.9 °C
since 1940
+0.2 °C per decade · r² = 0.38 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
39.9 °C
25 June 1988
Coldest day
-29.0 °C
20 February 2015
Wettest day
74 mm
25 June 1968
Windiest day
53.0 km/h
15 March 1959
Strongest gust
105.5 km/h
10 November 1998
Hottest feels-like
44.3 °C
14 July 1995
Coldest feels-like
-34.5 °C
19 January 1994
Snowiest day
26.0 cm
1 December 1974
Sunniest day
15.0 h
10 June 1941
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -1.7 °C | -1.0 °C | 37 mm | -19 mm |
| Feb | 0.1 °C | -0.7 °C | 47 mm | -6 mm |
| Mar | 11.8 °C | +5.1 °C | 71 mm | -0 mm |
| Apr | 15.5 °C | +1.7 °C | 85 mm | -3 mm |
| May | 18.7 °C | -1.5 °C | 111 mm | +20 mm |
| Jun | 26.9 °C | +1.4 °C | 124 mm | +36 mm |
| Jul | 28.7 °C | +1.0 °C | 128 mm | +45 mm |
| Aug | 26.2 °C | -0.5 °C | 33 mm | -45 mm |
| Sep | 24.8 °C | +2.0 °C | 44 mm | -23 mm |
| Oct | 18.3 °C | +2.2 °C | 74 mm | +8 mm |
| Nov | 8.4 °C | 0.0 °C | 42 mm | -27 mm |
| Dec | 1.5 °C | -0.3 °C | 78 mm | +16 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Romulus?
Romulus has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.4 °C and it receives 872 mm of precipitation per year.
What is the hottest day ever recorded in Romulus?
The hottest day measured in Romulus between 1940 and 2025 was 25 June 1988, reaching 39.9 °C.
What is the coldest day in Romulus?
The coldest day measured in Romulus between 1940 and 2025 was 20 February 2015, at -29.0 °C.
Does it snow in Romulus?
Yes. Romulus gets on average 76.5 cm of snow per year and has around 123 frost days.
Has the climate of Romulus warmed?
Yes: Romulus warmed by +1.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Romulus?
The wettest day measured in Romulus between 1940 and 2025 was 25 June 1968, with 74 mm of rain in 24 hours.
What was the windiest day in Romulus?
The windiest day measured in Romulus between 1940 and 2025 was 15 March 1959, with winds reaching 53.0 km/h.
What is the warmest month in Romulus?
The warmest month in Romulus is July (22.5 °C on average); the coldest is January (-4.3 °C).
How much does it rain in Romulus?
Romulus receives on average 872 mm of precipitation per year, spread over about 120 rainy days.
Is it sunny in Romulus?
Romulus gets on average 8.7 hours of sunshine per day, roughly 3,175 hours per year over 1940-2025.
What is the biggest single-day snowfall in Romulus?
The heaviest 24-hour snowfall measured in Romulus between 1940 and 2025 was 1 December 1974, with 26.0 cm.
Are there tropical nights in Romulus?
Yes: Romulus has on average 19 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Romulus?
In Romulus, between 1940 and 2025, the highest apparent temperature reached 44.3 °C on 14 July 1995, and the lowest was -34.5 °C on 19 January 1994.
Compare Romulus with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Romulus