Rochelle, Illinois · field elev 781 ft
Density Altitude at Rochelle Municipal/Koritz Field (KRPJ)
Rochelle Municipal/Koritz Field sits at 781 ft, and even a typical July afternoon (82 °F) only lifts density altitude to about 2,459 ft — heat still trims performance, but the field rarely turns high-and-hot.
Typical density altitude by month
| Month | Avg temp °F | DA at avg temp | Afternoon high °F | DA on a typical afternoon |
|---|---|---|---|---|
| January | 20.1 | −1,687 ft | 28.1 | −1,117 ft |
| February | 23.8 | −1,422 ft | 32.1 | −836 ft |
| March | 35.6 | −593 ft | 45.1 | 57 ft |
| April | 47.6 | 226 ft | 58.7 | 962 ft |
| May | 59.0 | 982 ft | 70.0 | 1,692 ft |
| June | 68.9 | 1,622 ft | 79.2 | 2,273 ft |
| July | 71.8 | 1,807 ft | 82.2 | 2,459 ft |
| August | 70.2 | 1,705 ft | 80.7 | 2,366 ft |
| September | 63.4 | 1,268 ft | 75.0 | 2,009 ft |
| October | 51.0 | 454 ft | 62.2 | 1,191 ft |
| November | 37.7 | −448 ft | 46.6 | 159 ft |
| December | 26.0 | −1,266 ft | 33.7 | −725 ft |
▲ above 5,000 ft · ⚠ above 8,000 ft. These are planning references at standard pressure and dry air — afternoon humidity and low pressure both push the real number higher. Run today's values below.
Run today’s numbers for KRPJ
DENSITY ALTITUDE
Field elevation 781 ft — the air behaves like 2,447 ft.
- PRESSURE ALT
- 782 ft
- ISA DEVIATION
- —
- RULE-OF-THUMB DA
- —
- AIR DENSITY INDEX
- —
- AIR DENSITY
- —
- WATER · GRAINS/LB
- —
For training and reference · verify with official sources and your POH before flight · no tool on this site renders a go / no-go judgment
Nearby Illinois fields
- C82 — Bresson
Compton · elev 769 ft
- C55 — Ogle County
Mount Morris · elev 929 ft
- C73 — Dixon Municipal-Charles R Walgreen Field
Dixon · elev 785 ft
- KDKB — De Kalb Taylor Municipal
De Kalb · elev 913 ft
- KRFD — Chicago/Rockford International
Chicago/Rockford · elev 742 ft
- 0C2 — Hinckley
Hinckley · elev 760 ft
- 1C8 — Cottonwood
Rockford · elev 741 ft
- KARR — Aurora Municipal
Chicago/Aurora · elev 712 ft
Frequently asked questions
How high does density altitude get at KRPJ in summer?
On a typical July afternoon — around 82 °F at the nearest NOAA normals station — density altitude at Rochelle Municipal/Koritz Field reaches roughly 2,459 ft at standard pressure. Hotter-than-normal days, low pressure, and humidity all push it higher, so run the day's actual numbers before flying.
What is the density altitude at KRPJ on an average day?
It swings with the seasons: from roughly −1,687 ft at the coldest month's average temperature to about 1,807 ft at the warmest month's — all from a constant field elevation of 781 ft. The month-by-month table above carries the full year.
What is the field elevation of Rochelle Municipal/Koritz Field?
781 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KRPJ (ICAO) / RPJ (FAA), in Rochelle, Illinois.