USDA Hardiness Zone 4b
Frost Dates for 59634 — Clancy, Montana
NOAA 1991–2020 normals from Tizer Gardens, MT (4,672 ft), 8 miles south.
Updated
In Clancy, the last spring frost (32°F) is around June 18 in half of years and has passed by July 3 in nine years out of ten. The first fall frost comes around September 5, as early as August 21 one year in ten, leaving a typical freeze-free season of 81 days (NOAA, Tizer Gardens, MT).
- Last spring frost
- June 18
- First fall frost
- September 5
- Growing season
- 81 days
- Hardiness zone
- 4b
50% probability
50% probability
freeze-free, 50%
-25 to -20°F (-31.7 to -28.9°C) coldest night
- First snow
- October 26
- Last snow
- April 16
- Winters with snow
- 100%
- Snow per year
- 37.2"
median, 1991–2020
median, 1991–2020
21 of 21 observed
NOAA normal
Frost risk by date in Clancy
Half of springs at Tizer Gardens, MT see their last 32°F night by June 18; only one in ten is past it by May 30, and one in ten still has one after July 3. Planting tender crops after June 24 leaves a 30% risk of a frost on them, after June 28 20%, and after July 3 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 53% of the 68 Montana stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 5 in half of years, as early as August 21 one year in ten, and holds off past September 18 one year in ten. A hard freeze of 28°F follows 13 days later, around September 18; in spring the one-in-ten date for 28°F is June 19, 14 days before the 32°F one. The freeze-free season lasts 81 days in a typical year, shorter than at 99% of the 68 Montana stations; it reaches 102 days one year in ten and falls short of 58 one year in ten. On average 223 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between October 21 and April 13.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | May 30 | Jun 4 | Jun 10 | Jun 14 | Jun 18 | Jun 21 | Jun 24 | Jun 28 | Jul 3 |
| 28°F | May 12 | May 18 | May 21 | May 25 | May 29 | Jun 1 | Jun 6 | Jun 11 | Jun 19 |
| 24°F | Apr 27 | May 2 | May 5 | May 8 | May 12 | May 14 | May 17 | May 21 | May 28 |
| 20°F | Apr 8 | Apr 15 | Apr 20 | Apr 24 | Apr 28 | Apr 30 | May 3 | May 7 | May 12 |
| 16°F | Mar 27 | Apr 2 | Apr 5 | Apr 8 | Apr 13 | Apr 17 | Apr 23 | Apr 28 | May 3 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Aug 21 | Aug 27 | Aug 30 | Sep 2 | Sep 5 | Sep 8 | Sep 11 | Sep 14 | Sep 18 |
| 28°F | Sep 4 | Sep 10 | Sep 13 | Sep 16 | Sep 18 | Sep 21 | Sep 23 | Sep 26 | Oct 1 |
| 24°F | Sep 17 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 10 | Oct 16 |
| 20°F | Sep 26 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 30 |
| 16°F | Oct 2 | Oct 8 | Oct 14 | Oct 17 | Oct 21 | Oct 25 | Oct 30 | Nov 3 | Nov 9 |
Freeze probabilities 1991–2020 at Tizer Gardens, MT, 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 59634 →Compare Clancy with another place →
Weather by month in Clancy
July is the warmest month at Tizer Gardens, MT, averaging 81°F by day and 44°F at night; December is the coldest at 33°F and 10°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). No month is safe from a 32°F night: even the warmest has at least a 10% chance. In spring, June still brings one in 86% of years and July still brings one in 14% of years.
Warmth for growing adds up to 1,209 growing degree days a year (base 50°F), fewer than at 97% of the 68 Montana stations. 20% of them (240) have built up by the end of June, and July adds the most, 402.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 35 | 10 | 100% | 30 | 0 |
| Feb | 36 | 11 | 100% | 27 | 1 |
| Mar | 46 | 18 | 100% | 30 | 1 |
| Apr | 54 | 25 | 100% | 27 | 7 |
| May | 62 | 33 | 100% | 14 | 59 |
| Jun | 71 | 39 | 86% | 3 | 171 |
| Jul | 81 | 44 | 14% | 1 | 402 |
| Aug | 82 | 43 | 34% | 1 | 382 |
| Sep | 71 | 35 | 99% | 9 | 158 |
| Oct | 56 | 26 | 100% | 23 | 26 |
| Nov | 43 | 19 | 100% | 28 | 1 |
| Dec | 33 | 10 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Tizer Gardens, MT (4,672 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, Helena Regional Airport, MT, 9 miles north of Clancy and 844 feet lower, has a last frost 40 days earlier (May 9), a first frost 25 days later (September 30), a season 61 days longer.
When it snows in Clancy, Montana
The first measurable snow (0.1 inch or more) in Clancy usually arrives around October 26, and the last of the season around April 16. Those are the middle dates across the winters of 1991–2020 at Helena Regional Airport, MT, 8.7 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 63 days after the last snow.
Planting calendar for 59634
| When | What to do |
|---|---|
| April 9 – April 23 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 23 – May 7 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 21 – June 4 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 18 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by August 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 5 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 59634 is 8 miles from Tizer Gardens, MT, which stands at 4,672 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 59634 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°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.