Updated October 2026
Lewis and Clark National Historical Park Weather by Month
Lewis and Clark National Historical Park is warmest in August, when the nearest NOAA climate station averages a high of 69°F and a low of 54°F, and coldest in February, with an average high of 51°F and an average low of 37°F. November is the wettest month, with about 11.1 inches of precipitation.
These figures are NOAA's 1991–2020 climate normals, the 30-year average for each calendar month, from the nearest long-record weather station, 5.4 miles from the park's reference point. A single station cannot describe a whole park: temperatures elsewhere in Lewis and Clark National Historical Park can differ from these, particularly with elevation.
Warmest month
Aug
69°F avg high
Coldest month
Feb
37°F avg low
Wettest month
Nov
11.1 in avg
Longest days
Jun
15.6 h of daylight
Average weather at Lewis and Clark by month
| Month | Avg high | Avg low | Precipitation | Daylight |
|---|---|---|---|---|
| January | 49°F | 38°F | 10.6 in | 8.8 h |
| February | 51°F | 37°F | 7.2 in | 10.1 h |
| March | 53°F | 39°F | 7.9 in | 11.6 h |
| April | 56°F | 42°F | 5.8 in | 13.3 h |
| May | 61°F | 46°F | 3.4 in | 14.8 h |
| June | 64°F | 51°F | 2.3 in | 15.6 h |
| July | 67°F | 54°F | 0.8 in | 15.2 h |
| August | 69°F | 54°F | 1.1 in | 14.0 h |
| September | 68°F | 51°F | 2.7 in | 12.3 h |
| October | 61°F | 45°F | 6.7 in | 10.6 h |
| November | 54°F | 40°F | 11.1 in | 9.2 h |
| December | 49°F | 38°F | 10.7 in | 8.4 h |
| Year total | 70.3 in |
NOAA 1991–2020 climate normals from station USW00094224, 5.4 miles from the park's reference point. Daylight is the monthly average, computed from the park's latitude. Each month links to how crowded Lewis and Clark is at that time of year.
Lewis and Clark weather by season
Winter: December to February
Average highs hold near 50°F in all three months, with average lows near 38°F. Together the three months average 28.5 inches of precipitation, about 41% of the yearly total and more than in any other season. Daylight is at its shortest, about 8.4 hours in December.
Spring: March to May
Average highs climb from 53°F in March to 61°F in May, with average lows between 39°F and 46°F. Together the three months average 17.1 inches of precipitation, about 24% of the yearly total. Daylight lengthens from about 11.6 hours in March to 14.8 in May.
Summer: June to August
Average highs climb from 64°F in June to 69°F in August, with average lows between 51°F and 54°F. Together the three months average 4.2 inches of precipitation, about 6% of the yearly total and less than in any other season. Daylight is at its longest, about 15.6 hours in June.
Fall: September to November
Average highs fall from 68°F in September to 54°F in November, with average lows between 40°F and 51°F. Together the three months average 20.5 inches of precipitation, about 29% of the yearly total. Daylight shortens from about 12.3 hours in September to 9.2 in November.
What the National Park Service says about the weather
We see an average of 70 inches of rain a year and we are the foggiest location in the Lower 48 states. Summer months are usually nice with days ranging from 55-70 degrees. Winters are wet and mild, usually 40-55 degrees. During the 106 days the Lewis and Clark Expedition wintered at Fort Clatsop in 1806 it rained all but 12 days and they saw the sun 6 times. While we are usually not so dreary make sure to prepare for rain or shine.
Weather description courtesy of the National Park Service — official park site.
Today's forecast for Lewis and Clark
Averages describe a typical month, not this week. For current conditions and the seven-day outlook, the National Weather Service issues a forecast for the park's reference point at 46.21°N, 123.96°W. It covers that one spot, so other elevations in the park can differ from it, as they do from the averages above.
National Weather Service forecast for Lewis and Clark National Historical Park →
Weather and crowds together
August, the warmest month, sees about 1.8× the visitors of the park's average month. July is the busiest month of the year and December the quietest. To see those crowds set against the weather for all twelve months, read the best time to visit Lewis and Clark National Historical Park. For hotels, cabins and rentals close to the park, see where to stay near Lewis and Clark.
Where to stay near Lewis and Clark
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Frequently Asked Questions
August is the warmest month at Lewis and Clark National Historical Park, with an average high of 69°F and an average low of 54°F. That is the 1991–2020 average at the nearest long-record NOAA station, 5.4 miles from the park's reference point. Temperatures inside the park can differ, particularly with elevation.
February is the coldest month at Lewis and Clark National Historical Park, with an average low of 37°F and an average high of 51°F, based on NOAA 1991–2020 climate normals.
November is the wettest month, with about 11.1 inches of precipitation. July is the driest, at about 0.8 inches. The station records about 70.3 inches of precipitation in an average year.
Daylight at Lewis and Clark National Historical Park runs from about 8.4 hours a day in December to about 15.6 hours in June, computed from the park's latitude.
Weather at nearby parks
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111 mi away · warmest in August (75°F)
116 mi away · warmest in August (64°F)
123 mi away · warmest in August (77°F)
Keep exploring
Sources: NOAA NCEI U.S. Climate Normals 1991–2020 (station USW00094224), daylight computed from latitude, weather description from the National Park Service, crowd levels from National Park Service Visitor Use Statistics (1979–2025). Updated 2026-10-11. Lodging results are provided by Stay22; WhenToVisitParks may earn a commission from bookings, at no extra cost to you.