Olney climate — normals and trends
Olney (United States) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 12.9 °C and it receives 1,062 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 (24.9 °C on average) and the coldest is January (0.6 °C). Rainfall peaks in July.
Olney averages 78 frost days, 45 hot days (≥ 30 °C) and 116 rainy days per year.
Olney has warmed by +1.7 °C between 1940 and 2025, or +0.19 °C per decade. This trend is statistically significant.
The number of frost days there went from about 86 to 70 per year over the period.
The hottest day of the period reached 39.3 °C (on 22 July 2011) and the coldest -24.4 °C (on 22 January 1984).
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
OlneyMaryland
- coords
- 39.15°, -77.07°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
12.9°C
Average daily high
17.8°C
Average daily low
8.5°C
Annual rainfall
1,062mm
Sunshine / day
9.0h
Mean relative humidity
67%
Average peak wind
16.1km/h
Seasonal range
24.3°C
Frost days (< 0 °C)
78 d/yr
Hot days (≥ 30 °C)
45 d/yr
Rainy days (≥ 1 mm)
116 d/yr
Annual snowfall
49.8 cm
Average feels-like high
16.5 °C
Average feels-like low
6.3 °C
Average peak gust
38.2 km/h
Tropical nights (≥ 20 °C)
49 d/yr
Solar radiation
15.0 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.7 °C
since 1940
+0.2 °C per decade · r² = 0.40 · 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
39.3 °C
22 July 2011
Coldest day
-24.4 °C
22 January 1984
Wettest day
159 mm
14 September 1966
Windiest day
50.7 km/h
1 December 1974
Strongest gust
123.5 km/h
15 October 1954
Hottest feels-like
45.1 °C
22 July 2011
Coldest feels-like
-30.2 °C
19 January 1994
Snowiest day
42.8 cm
20 March 1958
Sunniest day
14.3 h
24 June 2024
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 | 2.6 °C | -2.0 °C | 47 mm | -32 mm |
| Feb | 6.6 °C | +0.2 °C | 76 mm | +0 mm |
| Mar | 15.9 °C | +4.5 °C | 56 mm | -39 mm |
| Apr | 19.5 °C | +1.8 °C | 73 mm | -16 mm |
| May | 22.6 °C | -0.4 °C | 201 mm | +102 mm |
| Jun | 28.7 °C | +0.9 °C | 130 mm | +39 mm |
| Jul | 30.8 °C | +0.7 °C | 249 mm | +148 mm |
| Aug | 26.7 °C | -2.2 °C | 28 mm | -65 mm |
| Sep | 25.6 °C | +0.5 °C | 71 mm | -23 mm |
| Oct | 19.2 °C | +0.2 °C | 63 mm | -15 mm |
| Nov | 12.9 °C | +0.4 °C | 42 mm | -41 mm |
| Dec | 5.2 °C | -1.5 °C | 55 mm | -30 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 Olney?
Olney has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 12.9 °C and it receives 1,062 mm of precipitation per year.
What is the hottest day ever recorded in Olney?
The hottest day measured in Olney between 1940 and 2025 was 22 July 2011, reaching 39.3 °C.
What is the coldest day in Olney?
The coldest day measured in Olney between 1940 and 2025 was 22 January 1984, at -24.4 °C.
Does it snow in Olney?
Yes. Olney gets on average 49.8 cm of snow per year and has around 78 frost days.
Has the climate of Olney warmed?
Yes: Olney warmed by +1.7 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Olney?
The wettest day measured in Olney between 1940 and 2025 was 14 September 1966, with 159 mm of rain in 24 hours.
What was the windiest day in Olney?
The windiest day measured in Olney between 1940 and 2025 was 1 December 1974, with winds reaching 50.7 km/h.
What is the warmest month in Olney?
The warmest month in Olney is July (24.9 °C on average); the coldest is January (0.6 °C).
How much does it rain in Olney?
Olney receives on average 1,062 mm of precipitation per year, spread over about 116 rainy days.
Is it sunny in Olney?
Olney gets on average 9.0 hours of sunshine per day, roughly 3,285 hours per year over 1940-2025.
What is the biggest single-day snowfall in Olney?
The heaviest 24-hour snowfall measured in Olney between 1940 and 2025 was 20 March 1958, with 42.8 cm.
Are there tropical nights in Olney?
Yes: Olney has on average 49 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Olney?
In Olney, between 1940 and 2025, the highest apparent temperature reached 45.1 °C on 22 July 2011, and the lowest was -30.2 °C on 19 January 1994.
Compare Olney with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Olney