Average Weather in Lewiston Utah, United States
In Lewiston, the summers are hot and mostly clear, the winters are freezing and partly cloudy, and it is dry year round. Over the course of the year, the temperature typically varies from 16°F to 89°F and is rarely below 1°F or above 95°F.
Based on the tourism score, the best time of year to visit Lewiston for warm-weather activities is from late June to late August.
The hot season lasts for 3.1 months, from June 10 to September 15, with an average daily high temperature above 78°F. The hottest day of the year is July 26, with an average high of 89°F and low of 54°F.
The cold season lasts for 3.1 months, from November 24 to February 27, with an average daily high temperature below 42°F. The coldest day of the year is January 7, with an average low of 16°F and high of 31°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
In Lewiston, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Lewiston begins around June 5 and lasts for 4.4 months, ending around October 19. On July 27, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 80% of the time, and overcast or mostly cloudy 20% of the time.
The cloudier part of the year begins around October 19 and lasts for 7.6 months, ending around June 5. On March 3, the cloudiest day of the year, the sky is overcast or mostly cloudy 55% of the time, and clear, mostly clear, or partly cloudy 45% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Lewiston varies throughout the year.
The wetter season lasts 8.7 months, from September 21 to June 12, with a greater than 17% chance of a given day being a wet day. The chance of a wet day peaks at 26% on May 4.
The drier season lasts 3.3 months, from June 12 to September 21. The smallest chance of a wet day is 8% on July 4.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Lewiston changes throughout the year.
Rain alone is the most common for 11 months, from February 3 to December 21. The highest chance of a day with rain alone is 25% on May 20.
Mixed snow and rain is the most common for 3.9 weeks, from January 7 to February 3. The highest chance of a day with mixed snow and rain is 8% on January 8.
Snow alone is the most common for 2.4 weeks, from December 21 to January 7. The highest chance of a day with snow alone is 9% on December 28.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Lewiston experiences some seasonal variation in monthly rainfall.
Rain falls throughout the year in Lewiston. The most rain falls during the 31 days centered around May 18, with an average total accumulation of 1.8 inches.
The least rain falls around July 9, with an average total accumulation of 0.5 inches.
Average Monthly Rainfall
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Lewiston experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 5.0 months, from October 30 to March 28, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 5, with an average total liquid-equivalent accumulation of 0.6 inches.
The snowless period of the year lasts for 7.0 months, from March 28 to October 30. The least snow falls around August 4, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Lewiston varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 7 minutes of daylight; the longest day is June 21, with 15 hours, 14 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:51 AM on June 14, and the latest sunrise is 2 hours, 11 minutes later at 8:02 AM on November 3. The earliest sunset is at 4:55 PM on December 8, and the latest sunset is 4 hours, 11 minutes later at 9:07 PM on June 27.
Daylight saving time (DST) is observed in Lewiston during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
The perceived humidity level in Lewiston, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.
Humidity Comfort Levels
The average hourly wind speed in Lewiston experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 4.0 months, from February 25 to June 27, with average wind speeds of more than 6.7 miles per hour. The windiest day of the year is March 30, with an average hourly wind speed of 7.4 miles per hour.
The calmer time of year lasts for 8.0 months, from June 27 to February 25. The calmest day of the year is August 4, with an average hourly wind speed of 6.0 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Lewiston varies throughout the year.
The wind is most often from the west for 4.8 months, from March 16 to August 11 and for 1.1 months, from September 9 to October 12, with a peak percentage of 38% on May 4. The wind is most often from the south for 4.1 weeks, from August 11 to September 9 and for 5.1 months, from October 12 to March 16, with a peak percentage of 34% on September 2.
Best Time of Year to Visit
To characterize how pleasant the weather is in Lewiston throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Lewiston for general outdoor tourist activities is from late June to late August, with a peak score in the last week of July.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Lewiston for hot-weather activities is from early July to mid August, with a peak score in the last week of July.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
The growing season in Lewiston typically lasts for 4.6 months (140 days), from around May 11 to around September 28, rarely starting before April 21 or after May 29, and rarely ending before September 11 or after October 16.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Lewiston should appear around April 23, only rarely appearing before April 9 or after May 10.
Growing Degree Days
The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.
The brighter period of the year lasts for 3.0 months, from May 19 to August 17, with an average daily incident shortwave energy per square meter above 7.1 kWh. The brightest day of the year is June 29, with an average of 8.4 kWh.
The darker period of the year lasts for 3.5 months, from October 30 to February 14, with an average daily incident shortwave energy per square meter below 3.3 kWh. The darkest day of the year is December 21, with an average of 2.0 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Lewiston are 41.976 deg latitude, -111.856 deg longitude, and 4,501 ft elevation.
The topography within 2 miles of Lewiston is essentially flat, with a maximum elevation change of 75 feet and an average elevation above sea level of 4,500 feet. Within 10 miles is essentially flat (5,322 feet). Within 50 miles also contains extreme variations in elevation (5,722 feet).
The area within 2 miles of Lewiston is covered by cropland (88%), within 10 miles by cropland (56%) and shrubs (24%), and within 50 miles by shrubs (50%) and cropland (18%).
This report illustrates the typical weather in Lewiston, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Lewiston.
For each station, the records are corrected for the elevation difference between that station and Lewiston according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Lewiston is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Lewiston and a given station.
The stations contributing to this reconstruction are: Logan-Cache Airport (69%, 21 kilometers, south); Malad City Airport (26%, 40 kilometers, northwest); and Afton Municipal Airport (4.9%, 111 kilometers, northeast).
Time zones for aiports and weather stations are provided by AskGeo.com .