Boswell, Indiana climate: Normal weather by month, frost dates and records
Boswell's normal year runs from 15°F January nights to 83°F July afternoons, with 40.2 inches of precipitation and 17 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.9°C, January lows of −9°C, July highs of 28°C, 1,022 mm of precipitation a year.
- NOAA stationBoswell (4 mi WNW)
- Station IDUSC00120858
- Location40.53°N 87.45°W
- Elevation772 ft (235 m)
- Population811
On October 23, the normal high in Boswell is 61°F and the normal low 38°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 Boswell.
- Jan 32° 15°
- Feb 36° 18°
- Mar 48° 28°
- Apr 61° 38°
- May 73° 50°
- Jun 81° 60°
- Jul 83° 62°
- Aug 82° 59°
- Sep 77° 51°
- Oct 65° 40°
- Nov 49° 30°
- Dec 37° 21°
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 Boswell each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 15°F. The most precipitation falls in June (5.21 in), the least in February (1.86 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 32°F | 15°F | 23.5°F | 2.24 | 7.1 | 7 | <1 | 29 | 9 h 30 min |
| February | 36°F | 18°F | 27.1°F | 1.86 | 2.8 | 6 | <1 | 26 | 10 h 40 min |
| March | 48°F | 28°F | 37.6°F | 2.65 | 2.1 | 8 | <1 | 23 | 11 h 50 min |
| April | 61°F | 38°F | 49.5°F | 3.91 | 0.2 | 9 | <1 | 9 | 13 h 10 min |
| May | 73°F | 50°F | 61.2°F | 4.57 | 0.0 | 11 | <1 | 1 | 14 h 20 min |
| June | 81°F | 60°F | 70.1°F | 5.21 | 0.0 | 10 | 4 | <1 | 15 h |
| July | 83°F | 62°F | 72.4°F | 4.87 | 0.0 | 9 | 4 | <1 | 14 h 50 min |
| August | 82°F | 59°F | 70.5°F | 3.24 | 0.0 | 8 | 4 | <1 | 13 h 50 min |
| September | 77°F | 51°F | 64.3°F | 3.39 | 0.0 | 7 | 2 | <1 | 12 h 30 min |
| October | 65°F | 40°F | 52.5°F | 3.17 | 0.0 | 7 | <1 | 6 | 11 h 10 min |
| November | 49°F | 30°F | 39.7°F | 2.98 | 0.6 | 8 | <1 | 18 | 10 h |
| December | 37°F | 21°F | 28.7°F | 2.15 | 4.3 | 7 | <1 | 28 | 9 h 20 min |
| Year (annual) | 60°F | 39°F | 49.8°F | 40.24 | 17.1 | 96 | 13 | 138 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −9°C | −4.7°C | 57 mm | 18 cm |
| February | 2°C | −8°C | −2.7°C | 47 mm | 7 cm |
| March | 9°C | −2°C | 3.1°C | 67 mm | 5 cm |
| April | 16°C | 3°C | 9.7°C | 99 mm | 1 cm |
| May | 23°C | 10°C | 16.2°C | 116 mm | 0 cm |
| June | 27°C | 15°C | 21.2°C | 132 mm | 0 cm |
| July | 28°C | 17°C | 22.4°C | 124 mm | 0 cm |
| August | 28°C | 15°C | 21.4°C | 82 mm | 0 cm |
| September | 25°C | 11°C | 17.9°C | 86 mm | 0 cm |
| October | 18°C | 5°C | 11.4°C | 81 mm | 0 cm |
| November | 10°C | −1°C | 4.3°C | 76 mm | 2 cm |
| December | 3°C | −6°C | −1.8°C | 55 mm | 11 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00120858; 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 Boswell?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September 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 USC00120858.
When is the last frost in Boswell?
In Boswell, the last spring frost (32°F) comes after April 25 in half of years and after May 12 in one year in ten; the first autumn frost comes before October 13 in half of years and before September 27 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 251 year in 10 after May 12; 9 in 10 after April 13
- First autumn frost, half of years before
- October 131 year in 10 before September 27; 9 in 10 before October 25
NOAA puts the median frost-free season at 169 days, and the season without a hard freeze (28°F) at 190 days.
A hard freeze (28°F) comes after April 15 in half of springs and before October 22 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Boswell in zone 5b in ZIP code 47921, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Boswell's NOAA station is in zone 5b: the coldest night of a typical year reaches −14°F (15 complete years).
Frost dates for every NOAA station in Indiana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00120858; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. 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 Boswell?
In a normal year in Boswell, 13 days a year reach 90°F, 138 nights fall to 32°F or colder and 96 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
- 138a normal year
- Days that stay below freezing
- 44high of 32°F or less
- Days with 0.01 inch of precipitation
- 96a normal year
- Days with 1 inch of snow or more
- 7a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00120858.
How sunny is Boswell?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Boswell, 4.0 kWh per square metre a day. July is the sunniest month (81%) and December the cloudiest (60%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 62% | 1.8 |
| February | 66% | 2.7 |
| March | 67% | 3.6 |
| April | 70% | 4.8 |
| May | 72% | 5.5 |
| June | 79% | 6.3 |
| July | 81% | 6.3 |
| August | 81% | 5.6 |
| September | 80% | 4.6 |
| October | 72% | 3.1 |
| November | 69% | 2.1 |
| December | 60% | 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 Boswell need?
A normal year in Boswell brings 6,285 heating degree days, 17% more than the median U.S. place (5,373), and 768 cooling degree days, 15% 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 3,061 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,286 | 0 |
| February | 1,060 | 0 |
| March | 848 | 0 |
| April | 474 | 8 |
| May | 180 | 63 |
| June | 31 | 185 |
| July | 6 | 235 |
| August | 13 | 182 |
| September | 104 | 82 |
| October | 400 | 13 |
| November | 761 | 0 |
| December | 1,124 | 0 |
| Year (annual) | 6,285 | 768 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00120858. 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.
How does Boswell's climate compare?
Boswell is warmer than 9 of the other 98 places with their own NOAA record in Indiana, and wetter than 22. Across the 7,247 U.S. stations with normals, its annual mean of 49.8°F is warmer than 39%.
In the Köppen classification computed from these normals, Boswell 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 Boswell share this climate record?
4 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.
- Fowler, IN2,385 people · 9 mi NE
- Oxford, IN1,182 people · 11 mi E
- Milford, IL1,111 people · 14 mi NW
- Wellington, IL195 people · 12 mi W
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 Boswell's climate
What is the coldest month in Boswell?
January, with a normal high of 32°F and a normal low of 15°F. The warmest is July (83°F by day, 62°F at night).
Does it snow in Boswell?
Yes: 17 inches in a normal year, falling on 9 days with 0.1 inch or more, the most in January (7.1 inches).
What is the rainiest month in Boswell?
June, with 5.21 in of precipitation in a normal year; the driest is February with 1.86 in.
What plant hardiness zone is Boswell in?
The USDA's 2023 map puts Boswell in zone 5b in ZIP code 47921, the nearest ZIP area. By the same method at Boswell's NOAA station, the coldest night of a typical year reaches −14°F (15 years, 1991-2020): zone 5b.
How late can frost come in Boswell?
In half of years the last 32°F night comes after April 25; in one year in ten it comes after May 12. Waiting until May 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Indiana climateThe statewide normals and every place in the state
- Hoopeston, IL13 miles from this station, 52.2°F a year
- Kentland, IN16 miles from this station, 51.0°F a year
- Attica, IN22 miles from this station, 50.8°F a year
- Watseka, IL24 miles from this station, 50.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made