Frost Dates for Lewiston, ID

Based on data from Lewiston Nez Perce Co AP weather station, 3 miles away

Elevation: 745 ft

Frost Dates

Last Spring Frost (50%) A 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. April 6
First Fall Frost (50%) A 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. October 26

30% Probability

Only a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.
Last Spring Frost April 14
First Fall Frost October 18

Hard Freeze (28°F)

Last Spring Hard Freeze March 15
First Fall Hard Freeze November 8
46.42°N, 117.02°W © OpenStreetMap

Growing Season

203 Days April 6 to October 26

USDA Hardiness Zone

Hardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.
Zone 7b

Avg. annual minimum: 5 to 10°F

Learn more

Köppen Climate

The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
BSk Cold Semi-Arid (Steppe)

Cool to cold with low rainfall and wide temperature swings. Common in the western Great Plains and central Asia. Short growing seasons benefit from season extension techniques.

Köppen climate map

Temperature

Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)
Temperature table
Average monthly temperatures (°F)
Month Avg High Avg Temp Avg Low
January42°36°30°
February47°39°32°
March55°45°36°
April62°52°41°
May72°60°48°
June79°67°54°
July91°76°61°
August90°75°60°
September80°66°52°
October63°53°42°
November49°42°35°
December41°35°30°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January1.7
February1.7
March1.9
April2.4
May3.2
June2.6
July1.5
August1.9
September2.1
October2.1
November1.9
December1.9

Sunrise / Sunset

Daylight Pacific Time (PT) Longest: 15h 37m · Shortest: 8h 23m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (Pacific Time (PT))
Month Sunrise Sunset Daylight
January7:34 AM4:21 PM8h 47m
February7:00 AM5:05 PM10h 05m
March7:10 AM6:46 PM11h 36m
April6:08 AM7:28 PM13h 20m
May5:21 AM8:08 PM14h 47m
June5:01 AM8:36 PM15h 35m
July5:16 AM8:31 PM15h 15m
August5:53 AM7:52 PM13h 59m
September6:33 AM6:52 PM12h 19m
October7:14 AM5:52 PM10h 38m
November6:59 AM4:08 PM9h 09m
December7:32 AM3:56 PM8h 25m

Nearby Stations

Winchester, ID May 23 - September 25 Moscow U Of I, ID Pullman Moscow Rgnl AP, WA April 29 - October 2 Pullman 2 Nw, WA May 6 - September 29 Pomeroy, WAMay 2 - October 4 Dworshak Fish Hatchery, ID April 20 - October 20

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