Updated October 2026
Agate Fossil Beds National Monument Weather by Month
Agate Fossil Beds National Monument is warmest in July, when the nearest NOAA climate station averages a high of 87°F and a low of 53°F, and coldest in December, with an average high of 38°F and an average low of 8°F. May is the wettest month, with about 2.8 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, 0.9 miles from the park's reference point. A single station cannot describe a whole park: temperatures elsewhere in Agate Fossil Beds National Monument can differ from these, particularly with elevation.
Warmest month
Jul
87°F avg high
Coldest month
Dec
8°F avg low
Wettest month
May
2.8 in avg
Longest days
Jun
15.1 h of daylight
Average weather at Agate Fossil Beds by month
| Month | Avg high | Avg low | Precipitation | Daylight |
|---|---|---|---|---|
| January | 38°F | 9°F | 0.3 in | 9.2 h |
| February | 41°F | 12°F | 0.5 in | 10.3 h |
| March | 51°F | 20°F | 1.1 in | 11.7 h |
| April | 58°F | 28°F | 2.0 in | 13.2 h |
| May | 67°F | 38°F | 2.8 in | 14.4 h |
| June | 79°F | 47°F | 2.2 in | 15.1 h |
| July | 87°F | 53°F | 2.2 in | 14.8 h |
| August | 85°F | 49°F | 1.5 in | 13.7 h |
| September | 76°F | 39°F | 1.2 in | 12.3 h |
| October | 62°F | 27°F | 1.1 in | 10.8 h |
| November | 48°F | 17°F | 0.5 in | 9.5 h |
| December | 38°F | 8°F | 0.4 in | 8.9 h |
| Year total | 15.8 in |
NOAA 1991–2020 climate normals from station USW00094077, 0.9 miles from the park's reference point. Daylight is the monthly average, computed from the park's latitude. Each month links to how crowded Agate Fossil Beds is at that time of year.
Agate Fossil Beds weather by season
Winter: December to February
Average highs climb from 38°F in December to 41°F in February, with average lows between 8°F and 12°F. The average low is at or below freezing in all three months. Together the three months average 1.2 inches of precipitation, about 8% of the yearly total and less than in any other season. Daylight is at its shortest, about 8.9 hours in December.
Spring: March to May
Average highs climb from 51°F in March to 67°F in May, with average lows between 20°F and 38°F. The average low is at or below freezing in March and April. Together the three months average 5.9 inches of precipitation, about 37% of the yearly total. Daylight lengthens from about 11.7 hours in March to 14.4 in May.
Summer: June to August
Average highs peak at 87°F in July, between 79°F in June and 85°F in August, with average lows between 47°F and 53°F. Together the three months average 5.9 inches of precipitation, about 37% of the yearly total. Daylight is at its longest, about 15.1 hours in June.
Fall: September to November
Average highs fall from 76°F in September to 48°F in November, with average lows between 17°F and 39°F. The average low is at or below freezing in October and November. Together the three months average 2.8 inches of precipitation, about 18% of the yearly total. Daylight shortens from about 12.3 hours in September to 9.5 in November.
What the National Park Service says about the weather
Summers can be very warm, high 90's to 100 with the frequent afternoon thunderstorms. Plan to hike early and come down from the higher points if storms threaten. Winter temperatures can dip as low as -20 with snow and wind. Heaviest snows can be expected in late Spring.
Weather description courtesy of the National Park Service — official park site.
Today's forecast for Agate Fossil Beds
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 42.42°N, 103.75°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 Agate Fossil Beds National Monument →
Weather and crowds together
July, the warmest month, sees about 2.4× the visitors of the park's average month. August is the busiest month of the year and January the quietest. To see those crowds set against the weather for all twelve months, read the best time to visit Agate Fossil Beds National Monument. For hotels, cabins and rentals close to the park, see where to stay near Agate Fossil Beds.
Where to stay near Agate Fossil Beds
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Frequently Asked Questions
July is the warmest month at Agate Fossil Beds National Monument, with an average high of 87°F and an average low of 53°F. That is the 1991–2020 average at the nearest long-record NOAA station, 0.9 miles from the park's reference point. Temperatures inside the park can differ, particularly with elevation.
December is the coldest month at Agate Fossil Beds National Monument, with an average low of 8°F and an average high of 38°F, based on NOAA 1991–2020 climate normals.
May is the wettest month, with about 2.8 inches of precipitation. January is the driest, at about 0.3 inches. The station records about 15.8 inches of precipitation in an average year.
Daylight at Agate Fossil Beds National Monument runs from about 8.9 hours a day in December to about 15.1 hours in June, computed from the park's latitude.
Weather at nearby parks
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Sources: NOAA NCEI U.S. Climate Normals 1991–2020 (station USW00094077), 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.