USDA Hardiness Zone 6a
Frost Dates for 46978 — Royal Center, Indiana
NOAA 1991–2020 normals from Logansport Cicott St, IN (600 ft), 10 miles southeast.
Updated
In Royal Center, the last spring frost (32°F) is around April 20 in half of years and has passed by May 6 in nine years out of ten. The first fall frost comes around October 23, as early as October 11 one year in ten, leaving a typical freeze-free season of 185 days (NOAA, Logansport Cicott St, IN).
- Last spring frost
- April 20
- First fall frost
- October 23
- Growing season
- 185 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- December 9
- Last snow
- March 14
- Winters with snow
- 100%
- Snow per year
- 19.4"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Royal Center
Half of springs at Logansport Cicott St, IN see their last 32°F night by April 20; only one in ten is past it by April 6, and one in ten still has one after May 6. Planting tender crops after April 27 leaves a 30% risk of a frost on them, after May 1 20%, and after May 6 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 35% of the 125 Indiana stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 23 in half of years, as early as October 11 one year in ten, and holds off past November 5 one year in ten. A hard freeze of 28°F follows 11 days later, around November 3; in spring the one-in-ten date for 28°F is April 24, 12 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, longer than at 58% of the 125 Indiana stations; it reaches 203 days one year in ten and falls short of 165 one year in ten. On average 125 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about May 1, and return around October 14. Severe cold of 16°F or below comes every winter, usually between December 6 and March 6.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 17 | Apr 22 | Apr 26 | Apr 30 | May 1 | May 4 | May 7 | May 11 | May 16 |
| 32°F | Apr 6 | Apr 11 | Apr 15 | Apr 18 | Apr 20 | Apr 23 | Apr 27 | May 1 | May 6 |
| 28°F | Mar 25 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 19 | Apr 24 |
| 24°F | Mar 11 | Mar 17 | Mar 21 | Mar 25 | Mar 29 | Mar 31 | Apr 3 | Apr 7 | Apr 13 |
| 20°F | Feb 28 | Mar 6 | Mar 10 | Mar 13 | Mar 17 | Mar 20 | Mar 24 | Mar 30 | Apr 2 |
| 16°F | Feb 16 | Feb 24 | Mar 1 | Mar 3 | Mar 6 | Mar 10 | Mar 13 | Mar 18 | Mar 25 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 30 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 16 | Oct 18 | Oct 22 | Oct 25 |
| 32°F | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 5 |
| 28°F | Oct 22 | Oct 26 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 14 | Nov 19 |
| 24°F | Nov 1 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 28 | Dec 3 |
| 20°F | Nov 8 | Nov 14 | Nov 19 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 9 | Dec 17 |
| 16°F | Nov 18 | Nov 26 | Nov 30 | Dec 3 | Dec 6 | Dec 10 | Dec 15 | Dec 20 | Dec 26 |
Freeze probabilities 1991–2020 at Logansport Cicott St, IN, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 46978 →Compare Royal Center with another place →
Weather by month in Royal Center
July is the warmest month at Logansport Cicott St, IN, averaging 84°F by day and 63°F at night; January is the coldest at 33°F and 18°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 20% of years.
Warmth for growing adds up to 3,230 growing degree days a year (base 50°F), fewer than at 62% of the 125 Indiana stations. 35% of them (1,121) have built up by the end of June, and July adds the most, 741. Precipitation totals 41.4 inches a year, most in June (4.8") and least in February (2.0"); May to September bring 52% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 33 | 18 | 2.6 | 100% | 28 | 1 |
| Feb | 37 | 20 | 2.0 | 100% | 25 | 2 |
| Mar | 48 | 29 | 2.7 | 100% | 21 | 28 |
| Apr | 61 | 39 | 3.8 | 97% | 7 | 118 |
| May | 72 | 50 | 4.4 | 20% | <1 | 355 |
| Jun | 81 | 60 | 4.8 | 0% | 0 | 618 |
| Jul | 84 | 63 | 4.8 | 0% | 0 | 741 |
| Aug | 83 | 62 | 4.4 | 0% | 0 | 691 |
| Sep | 78 | 54 | 3.3 | 2% | <1 | 475 |
| Oct | 64 | 43 | 3.0 | 78% | 4 | 169 |
| Nov | 50 | 32 | 3.1 | 100% | 16 | 30 |
| Dec | 38 | 24 | 2.5 | 100% | 25 | 4 |
Monthly normals 1991–2020 at Logansport Cicott St, IN (600 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Winamac 2SSE, IN, 12 miles north of Royal Center, has a last frost 5 days later (April 25), a first frost 5 days earlier (October 18), a season 12 days shorter.
When it snows in Royal Center, Indiana
The first measurable snow (0.1 inch or more) in Royal Center usually arrives around December 9, and the last of the season around March 14. Those are the middle dates across the winters of 1991–2020 at Logansport Cicott St, IN, 9.8 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 37 days after the last snow.
Planting calendar for 46978
| When | What to do |
|---|---|
| February 9 – February 23 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 23 – March 9 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 23 – April 6 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 20 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 31 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 9 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 23 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 46978 is 10 miles from Logansport Cicott St, IN, which stands at 600 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 46947 (Logansport). The 2023 USDA Plant Hardiness Zone Map lists ZIP 46978 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.