Tusayan climate

Tusayan Frost Dates and Growing Season

NOAA 1991-2020 normals for Grand Canyon Np AP, 4 km from Tusayan, elevation 6606 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Grand Canyon Np AP. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around June 17 and the first fall freeze around September 24, a growing season of about 97 days.

Median at 36°F
last June 28, first September 15
Median at 32°F
last June 17, first September 24
Median at 28°F
last June 4, first October 3

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FJul 12Jul 5Jul 2Jun 30Jun 28Jun 25Jun 22Jun 19Jun 15
32°FJul 1Jun 26Jun 23Jun 20Jun 17Jun 14Jun 11Jun 7Jun 3
28°FJun 21Jun 15Jun 11Jun 8Jun 4Jun 1May 29May 22May 14
24°FJun 8Jun 3May 27May 20May 16May 12May 8May 4Apr 30
20°FMay 19May 12May 6May 3Apr 30Apr 26Apr 23Apr 19Apr 12
16°FMay 3Apr 26Apr 21Apr 16Apr 12Apr 7Apr 3Mar 30Mar 18

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 3Sep 6Sep 10Sep 12Sep 15Sep 17Sep 19Sep 22Sep 25
32°FSep 12Sep 16Sep 19Sep 21Sep 24Sep 26Sep 29Oct 2Oct 6
28°FSep 21Sep 25Sep 28Oct 1Oct 3Oct 5Oct 8Oct 12Oct 17
24°FSep 29Oct 3Oct 6Oct 10Oct 14Oct 17Oct 20Oct 25Nov 1
20°FOct 8Oct 14Oct 18Oct 22Oct 26Oct 30Nov 1Nov 6Nov 10
16°FOct 20Oct 26Oct 31Nov 3Nov 5Nov 9Nov 12Nov 16Nov 20

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F958883807774706558
32°F1161101051029794908680
28°F144137131126121117113108100
24°F172164158153148144139132124
20°F202194188182178172168162151
16°F233224218212206201196188179

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
6,799
Cooling degree days, base 65°F
162
Growing degree days, base 40°F
3,678
Growing degree days, base 45°F
2,624
Growing degree days, base 50°F
1,763
Growing degree days, base 55°F
1,067
Growing degree days, base 60°F
525

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,09000
February92300
March82901
April65309
May4300101
June15513311
July2282525
August2862499
September1954267
October533049
November83102
December1,11100

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 4 km from Tusayan. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00003195 (Grand Canyon Np AP). Public domain.