London, Ohio climate: Normal weather by month, frost dates and records
London's normal year runs from 19°F January nights to 82°F July afternoons, with 42.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.2°C, January lows of −7°C, July highs of 28°C, 1,074 mm of precipitation a year.
- NOAA stationLondon Fish Hatchery
- Station IDUSC00334681
- Location39.90°N 83.51°W
- Elevation1,120 ft (341 m)
- From the center4 miles
- Population10,743
On October 14, the normal high in London is 65°F and the normal low 42°F, and the chance of measurable rain or snow is 24%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for London.
- Jan 33° 19°
- Feb 37° 21°
- Mar 48° 29°
- Apr 61° 39°
- May 71° 50°
- Jun 79° 60°
- Jul 82° 63°
- Aug 81° 61°
- Sep 76° 53°
- Oct 64° 41°
- Nov 50° 32°
- Dec 39° 24°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in London each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 19°F. The most precipitation falls in July (4.96 in), the least in February (2.28 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 33°F | 19°F | 25.9°F | 3.12 | 10 | <1 | 28 | 9 h 40 min |
| February | 37°F | 21°F | 28.6°F | 2.28 | 8 | <1 | 24 | 10 h 40 min |
| March | 48°F | 29°F | 38.1°F | 3.70 | 9 | <1 | 22 | 11 h 50 min |
| April | 61°F | 39°F | 49.8°F | 4.05 | 11 | <1 | 9 | 13 h 10 min |
| May | 71°F | 50°F | 60.5°F | 4.67 | 11 | <1 | 1 | 14 h 20 min |
| June | 79°F | 60°F | 69.5°F | 4.71 | 10 | 3 | <1 | 15 h |
| July | 82°F | 63°F | 72.4°F | 4.96 | 10 | 6 | <1 | 14 h 50 min |
| August | 81°F | 61°F | 70.7°F | 2.87 | 7 | 3 | <1 | 13 h 50 min |
| September | 76°F | 53°F | 64.2°F | 2.91 | 7 | 2 | <1 | 12 h 30 min |
| October | 64°F | 41°F | 52.5°F | 2.83 | 7 | <1 | 6 | 11 h 10 min |
| November | 50°F | 32°F | 40.8°F | 2.96 | 8 | <1 | 18 | 10 h |
| December | 39°F | 24°F | 31.3°F | 3.22 | 8 | <1 | 25 | 9 h 20 min |
| Year (annual) | 60°F | 41°F | 50.4°F | 42.28 | 105 | 13 | 132 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 1°C | −7°C | −3.4°C | 79 mm |
| February | 3°C | −6°C | −1.9°C | 58 mm |
| March | 9°C | −2°C | 3.4°C | 94 mm |
| April | 16°C | 4°C | 9.9°C | 103 mm |
| May | 22°C | 10°C | 15.8°C | 119 mm |
| June | 26°C | 15°C | 20.8°C | 120 mm |
| July | 28°C | 17°C | 22.4°C | 126 mm |
| August | 27°C | 16°C | 21.5°C | 73 mm |
| September | 24°C | 12°C | 17.9°C | 74 mm |
| October | 18°C | 5°C | 11.4°C | 72 mm |
| November | 10°C | 0°C | 4.9°C | 75 mm |
| December | 4°C | −4°C | −0.4°C | 82 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Marysville (24 miles away), gets 24 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00334681; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit London?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August has the fewest days with rain (7).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00334681.
When is the last frost in London?
In London, the last spring frost (32°F) comes after April 24 in half of years and after May 10 in one year in ten; the first autumn frost comes before October 18 in half of years and before October 5 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 241 year in 10 after May 10; 9 in 10 after April 10
- First autumn frost, half of years before
- October 181 year in 10 before October 5; 9 in 10 before November 1
NOAA puts the median frost-free season at 175 days, and the season without a hard freeze (28°F) at 198 days.
A hard freeze (28°F) comes after April 14 in half of springs and before October 29 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts London in zone 6a in ZIP code 43140, the nearest ZIP area.
Frost dates for every NOAA station in Ohio · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00334681; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in London?
In a normal year in London, 13 days a year reach 90°F, 132 nights fall to 32°F or colder and 105 days bring measurable precipitation.
- Days at 90°F or more
- 13a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 132a normal year
- Days that stay below freezing
- 36high of 32°F or less
- Days with 0.01 inch of precipitation
- 105a normal year
The highest temperature in this station's record (since 1918) is 109°F, on July 9, 1936; the lowest is −24°F, on January 19, 1994.
The wettest calendar year on that record is 2018, with 52.18 in; the snowiest season is 1977–78, with 58.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00334681; records: ACIS (NOAA Regional Climate Centers), station USC00334681. Records use complete months only; a month missing more than three days is left out.
How sunny is London?
Over a year 72% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around London, 4.0 kWh per square metre a day. August is the sunniest month (81%) and December the cloudiest (57%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 58% | 1.8 |
| February | 62% | 2.6 |
| March | 65% | 3.6 |
| April | 71% | 4.9 |
| May | 73% | 5.6 |
| June | 78% | 6.2 |
| July | 79% | 6.0 |
| August | 81% | 5.5 |
| September | 79% | 4.6 |
| October | 72% | 3.2 |
| November | 69% | 2.2 |
| December | 57% | 1.5 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does London need?
A normal year in London brings 6,040 heating degree days, 12% more than the median U.S. place (5,373), and 741 cooling degree days, 18% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,022 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,212 | 0 |
| February | 1,018 | 0 |
| March | 835 | 1 |
| April | 461 | 5 |
| May | 191 | 53 |
| June | 32 | 165 |
| July | 7 | 236 |
| August | 12 | 188 |
| September | 107 | 84 |
| October | 396 | 10 |
| November | 726 | 0 |
| December | 1,046 | 0 |
| Year (annual) | 6,040 | 741 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00334681. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has London been warmer than normal lately?
2025 averaged 52.3°F, 1.9°F above the 1991-2020 normal of 50.4°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 52.1°F | +1.7°F | – |
| 2022 | 51.0°F | +0.6°F | 40.92 |
| 2023 | 53.4°F | +3.0°F | 40.30 |
| 2024 | 55.1°F | +4.7°F | 36.37 |
| 2025 | 52.3°F | +1.9°F | 42.03 |
Over 74 complete years from 1919 to 2025, the station's annual mean temperature rose at a fitted 2.1°F per century (+0.12°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00334681; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does London's climate compare?
London is warmer than 26 of the other 98 places with their own NOAA record in Ohio, and wetter than 57. Across the 7,247 U.S. stations with normals, its annual mean of 50.4°F is warmer than 42%.
In the Köppen classification computed from these normals, London is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near London share this climate record?
9 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- West Jefferson, OH4,943 people · 11 mi E
- Choctaw Lake, OH2,145 people · 4 mi N
- South Charleston, OH1,695 people · 9 mi SW
- South Vienna, OH407 people · 6 mi W
- South Solon, OH330 people · 12 mi SW
- Plumwood, OH289 people · 9 mi NE
- Midway, OH273 people · 11 mi S
- Catawba, OH242 people · 9 mi NW
- Lafayette, OH124 people · 6 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about London's climate
What is the coldest month in London?
January, with a normal high of 33°F and a normal low of 19°F. The warmest is July (82°F by day, 63°F at night).
Does it snow in London?
Yes. NOAA publishes no 1991-2020 snowfall normal for London's NOAA station; the nearest record that keeps one, Marysville (24 miles away), records 24 inches of snow in a normal year.
What is the rainiest month in London?
July, with 4.96 in of precipitation in a normal year; the driest is February with 2.28 in.
What plant hardiness zone is London in?
The USDA's 2023 map puts London in zone 6a in ZIP code 43140, the nearest ZIP area.
How late can frost come in London?
In half of years the last 32°F night comes after April 24; in one year in ten it comes after May 10. Waiting until May 10 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Ohio climateThe statewide normals and every place in the state
- Springfield, OH17 miles from this station, 51.2°F a year
- Urbana, OH20 miles from this station, 51.2°F a year
- Marysville, OH24 miles from this station, 52.3°F a year
- Washington Court House, OH25 miles from this station, 51.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made