When is the last frost in Azusa, CA?

The average last spring frost (50% probability of 32°F) in Azusa is around May 16, based on NOAA/NCEI 1991–2020 normals at the Wrightwood, CA station (10.8 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Azusa?

The average first fall frost in Azusa, CA is around October 13, giving roughly a 151-day frost-free growing season.

What planting zone is Azusa, CA?

Azusa is in USDA plant hardiness zone 9b (average annual extreme minimum temperature 25 to 30°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Azusa?

In Azusa, CA the warmest month is July (avg high 83.3°F) and the coldest is December (avg low 24.6°F). It averages about 21.1″ of precipitation a year and 61.8″ of snow.

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Azusa, CA Planting Calendar & Frost Dates

USDA hardiness zone 9b · ZIP 91702 · elevation 1829′ · NOAA & USDA data

Azusa is in USDA hardiness zone 9b (winters can dip to 25 to 30°F), with a growing season of about 151 days between the average last spring frost (May 16) and first fall frost (October 13). The warmest month is July (avg high 83.3°F); the coldest is December (avg low 24.6°F). It averages 21.1″ of precipitation a year and 61.8″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp 25 to 30°F

Last spring frost

May 16

avg (50% prob, 32°F)

First fall frost

October 13

avg (50% prob, 32°F)

Growing season

151 days

frost-free window

Warmest month

July

avg high 83.3°F

Month-by-month typical weather in Azusa

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Wrightwood, CA (10.8 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	47.6	25.6	36.6	4.4	10.5
February	47.6	25.3	36.4	4.9	24.8
March	54.3	29.3	41.8	1.9	8.3
April	60.3	32	46.1	0.8	7.2
May	69.1	38.8	54	0.8	1.6
June	78	44.3	61.2	0.1	0
July	83.3	52.5	67.9	1.1	0
August	81.9	51.4	66.7	0.3	0
September	75	46.2	60.6	0.4	0
October	64.4	36.7	50.5	1.2	0.5
November	54.8	28.8	41.8	1.1	3.6
December	47.5	24.6	36	4.1	5.3

What to plant when in Azusa

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: April 4 · Transplant out: May 23
Peppers	warm	Start seeds indoors: March 21 · Transplant out: May 30
Cucumbers	warm	Direct sow: May 23
Zucchini / squash	warm	Direct sow: May 23
Bush beans	warm	Direct sow: May 23
Sweet corn	warm	Direct sow: May 23
Basil	warm	Transplant out: May 23
Peas	cool	Sow (spring): April 11 · Sow (fall): August 18
Spinach	cool	Sow (spring): April 4 · Sow (fall): August 18
Lettuce	cool	Sow (spring): April 18 · Sow (fall): August 18
Kale	cool	Transplant (spring): April 25 · Sow (fall): August 4
Broccoli	cool	Transplant (spring): May 2
Carrots	cool	Sow (spring): April 25 · Sow (fall): August 4
Onions	cool	Transplant (spring): April 18
Potatoes	cool	Plant seed potatoes: May 2
Radishes	cool	Sow (spring): April 18 · Sow (fall): September 1

Dates are computed from Azusa's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

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Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Wrightwood, CA, 10.8 mi (confidence: medium). Monthly weather normals: Wrightwood, CA, 10.8 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.