Roy climate — normals and trends
Roy (United States) has a hot-summer mediterranean continental climate (Dsa) under the Köppen-Geiger classification. Its mean annual temperature is 8.5 °C and it receives 537 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 (23.2 °C on average) and the coldest is January (-4.7 °C). Rainfall peaks in April.
Roy averages 149 frost days, 37 hot days (≥ 30 °C) and 94 rainy days per year.
Roy has warmed by +2.8 °C between 1940 and 2025, or +0.33 °C per decade. This trend is statistically significant.
The number of frost days there went from about 166 to 132 per year over the period.
The hottest day of the period reached 37.8 °C (on 13 July 2002) and the coldest -30.6 °C (on 13 January 1963).
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
RoyUtah
- coords
- 41.16°, -112.03°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
8.5°C
Average daily high
14.2°C
Average daily low
2.5°C
Annual rainfall
537mm
Sunshine / day
10.6h
Mean relative humidity
59%
Average peak wind
10.6km/h
Seasonal range
27.9°C
Frost days (< 0 °C)
149 d/yr
Hot days (≥ 30 °C)
37 d/yr
Rainy days (≥ 1 mm)
94 d/yr
Annual snowfall
154.4 cm
Average feels-like high
11.9 °C
Average feels-like low
-0.7 °C
Average peak gust
34.8 km/h
Tropical nights (≥ 20 °C)
2 d/yr
Solar radiation
18.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.8 °C
since 1940
+0.3 °C per decade · r² = 0.50 · 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
37.8 °C
13 July 2002
Coldest day
-30.6 °C
13 January 1963
Wettest day
44 mm
4 July 1961
Windiest day
32.5 km/h
12 November 1973
Strongest gust
106.9 km/h
10 May 2004
Hottest feels-like
37.1 °C
13 July 2002
Coldest feels-like
-35.6 °C
13 January 1963
Snowiest day
23.0 cm
24 January 1954
Sunniest day
15.0 h
14 June 1940
Normals computed over complete calendar years 1940–2025.
A specific year
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Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -0.1 °C | +0.1 °C | 23 mm | -37 mm |
| Feb | 4.3 °C | +2.0 °C | 61 mm | +10 mm |
| Mar | 9.0 °C | +2.3 °C | 81 mm | +26 mm |
| Apr | 14.6 °C | +2.3 °C | 29 mm | -35 mm |
| May | 20.8 °C | +2.4 °C | 53 mm | -6 mm |
| Jun | 27.4 °C | +2.9 °C | 4 mm | -27 mm |
| Jul | 31.3 °C | +1.3 °C | 4 mm | -7 mm |
| Aug | 30.0 °C | +1.1 °C | 29 mm | +14 mm |
| Sep | 25.3 °C | +2.0 °C | 16 mm | -15 mm |
| Oct | 15.5 °C | -0.1 °C | 79 mm | +33 mm |
| Nov | 11.5 °C | +4.7 °C | 22 mm | -33 mm |
| Dec | 6.6 °C | +5.4 °C | 59 mm | -1 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 Roy?
Roy has a hot-summer mediterranean continental climate (Köppen Dsa). Over 1940-2025, the average annual temperature is 8.5 °C and it receives 537 mm of precipitation per year.
What is the hottest day ever recorded in Roy?
The hottest day measured in Roy between 1940 and 2025 was 13 July 2002, reaching 37.8 °C.
What is the coldest day in Roy?
The coldest day measured in Roy between 1940 and 2025 was 13 January 1963, at -30.6 °C.
Does it snow in Roy?
Yes. Roy gets on average 154.4 cm of snow per year and has around 149 frost days.
Has the climate of Roy warmed?
Yes: Roy warmed by +2.8 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Roy?
The wettest day measured in Roy between 1940 and 2025 was 4 July 1961, with 44 mm of rain in 24 hours.
What was the windiest day in Roy?
The windiest day measured in Roy between 1940 and 2025 was 12 November 1973, with winds reaching 32.5 km/h.
What is the warmest month in Roy?
The warmest month in Roy is July (23.2 °C on average); the coldest is January (-4.7 °C).
How much does it rain in Roy?
Roy receives on average 537 mm of precipitation per year, spread over about 94 rainy days.
Is it sunny in Roy?
Roy gets on average 10.6 hours of sunshine per day, roughly 3,869 hours per year over 1940-2025.
What is the biggest single-day snowfall in Roy?
The heaviest 24-hour snowfall measured in Roy between 1940 and 2025 was 24 January 1954, with 23.0 cm.
Are there tropical nights in Roy?
Yes: Roy has on average 2 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Roy?
In Roy, between 1940 and 2025, the highest apparent temperature reached 37.1 °C on 13 July 2002, and the lowest was -35.6 °C on 13 January 1963.
Compare Roy with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Roy