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USDA Hardiness Zone 6b

Frost Dates for 84403 — Ogden, Utah

NOAA 1991–2020 normals from Ogden Hinkley Airport, UT (4,470 ft), 3 miles west.

Updated

In Ogden, the last spring frost (32°F) is around April 22 in half of years and has passed by May 10 in nine years out of ten. The first fall frost comes around October 22, as early as October 7 one year in ten, leaving a typical freeze-free season of 180 days (NOAA, Ogden Hinkley Airport, UT).

Last spring frost
April 22

50% probability

First fall frost
October 22

50% probability

Growing season
180 days

freeze-free, 50%

Hardiness zone
6b

-5 to 0°F (-20.6 to -17.8°C) coldest night

First snow
November 5

median, 1991–2020

Last snow
April 17

median, 1991–2020

Winters with snow
100%

22 of 22 observed

Snow per year
107.9"

NOAA normal

Frost risk by date in Ogden

Half of springs at Ogden Hinkley Airport, UT see their last 32°F night by April 22; only one in ten is past it by April 4, and one in ten still has one after May 10. Planting tender crops after April 29 leaves a 30% risk of a frost on them, after May 3 20%, and after May 10 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 47% of the 66 Utah stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 22 in half of years, as early as October 7 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 11 days later, around November 2; in spring the one-in-ten date for 28°F is April 21, 19 days before the 32°F one. The freeze-free season lasts 180 days in a typical year, longer than at 77% of the 66 Utah stations; it reaches 204 days one year in ten and falls short of 158 one year in ten. On average 121 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 16 days longer, to about May 8, and return around October 11. Severe cold of 16°F or below comes every winter, usually between December 1 and February 16.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FApr 22Apr 28May 1May 4May 8May 12May 16May 23May 31
32°FApr 4Apr 11Apr 15Apr 19Apr 22Apr 26Apr 29May 3May 10
28°FMar 13Mar 20Mar 27Mar 31Apr 3Apr 7Apr 11Apr 16Apr 21
24°FFeb 25Mar 2Mar 5Mar 8Mar 12Mar 16Mar 22Mar 29Apr 3
20°FFeb 11Feb 16Feb 20Feb 24Feb 27Mar 2Mar 5Mar 9Mar 14
16°FJan 28Feb 4Feb 9Feb 12Feb 16Feb 19Feb 23Feb 27Mar 3
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 28Oct 2Oct 5Oct 7Oct 11Oct 14Oct 16Oct 21Oct 25
32°FOct 7Oct 12Oct 16Oct 19Oct 22Oct 25Oct 28Nov 1Nov 6
28°FOct 18Oct 23Oct 27Oct 30Nov 2Nov 5Nov 8Nov 12Nov 17
24°FOct 25Nov 1Nov 5Nov 8Nov 12Nov 15Nov 18Nov 22Nov 27
20°FNov 5Nov 10Nov 14Nov 18Nov 22Nov 25Nov 28Dec 2Dec 8
16°FNov 12Nov 19Nov 24Nov 28Dec 1Dec 5Dec 10Dec 15Dec 22

Freeze probabilities 1991–2020 at Ogden Hinkley Airport, UT, 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 84403 →Compare Ogden with another place →

Weather by month in Ogden

July is the warmest month at Ogden Hinkley Airport, UT, averaging 91°F by day and 65°F at night; January is the coldest at 36°F and 21°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 26% of years.

Warmth for growing adds up to 3,226 growing degree days a year (base 50°F), more than at 73% of the 66 Utah stations. 29% of them (943) have built up by the end of June, and July adds the most, 869. Precipitation totals 16.5 inches a year, most in May (2.2") and least in July (0.4"); May to September bring 33% of it.

Monthly normals 1991–2020 at Ogden Hinkley Airport, UT
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan36211.5100%290
Feb42251.6100%241
Mar53331.7100%1423
Apr60392.092%681
May70472.226%1286
Jun82551.11%0553
Jul91650.40%0869
Aug89630.70%0800
Sep78531.12%<1468
Oct63411.778%3133
Nov49311.2100%1713
Dec37221.3100%280

Monthly normals 1991–2020 at Ogden Hinkley Airport, UT (4,470 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, Ogden Pioneer Ph, UT, 4 miles north of Ogden, has a last frost 1 day earlier (April 21), a first frost 1 day later (October 23), a season 4 days longer.

Frost dates for 84401 (Ogden) →

When it snows in Ogden, Utah

The first measurable snow (0.1 inch or more) in Ogden usually arrives around November 5, and the last of the season around April 17. Those are the middle dates across the winters of 1991–2020 at Pineview Dam, UT, 7.4 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 5 days after the last snow.

Planting calendar for 84403

What to do and when, from the 50% frost dates for Ogden, Utah
WhenWhat to do
February 11 – February 25Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
February 25 – March 11Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
March 25 – April 8Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
April 22 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 30Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by October 8Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 22 onwardPlant 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 84403 is 3 miles from Ogden Hinkley Airport, UT, which stands at 4,470 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 84015 (Clearfield). The 2023 USDA Plant Hardiness Zone Map lists ZIP 84403 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across Utah →

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.

ZIP codes measured at the same station

Other zone 6b places in Utah