Forest County Climate Profile

Forest County is located in the northeastern part of Wisconsin, along the northern border of the state. The county is in a part of Wisconsin that is dominated by forests, wetlands, and freshwater lakes. Some of the Forest County Potawatomi and the Sokaogon (Mole Lake) Chippewa Community have called the county home since the 1800s. Forest County has a humid continental climate, characterized by precipitation year-round and summers that are warm to hot.

Records are computed using all available station data, some of which goes back to 1895 (Source: ACIS).

Averages for freeze dates are computed for the most recent 30 years (1996-2025; Source: ACIS).

Temperatures have been increasing since 1950 in Forest County on the annual and seasonal time scales, which is the case for most of Wisconsin. Since 1950, annual average temperatures in Forest County have increased at a rate of 0.4°F/decade, which translates to an increase of 1°F every 25 years. This increase in temperature has been most pronounced in the winter months and less pronounced in the other seasons. When annual average temperatures are split into daily high and low temperatures, low temperatures have been warming at a faster rate compared to high temperatures. In particular, winter minimum temperatures have been increasing by 1°F every 11 years since 1950.

With temperatures warming, this does not mean that every year will be warmer than the last, or that more recent years will all have above-average (1895-2025) temperatures. However, Forest County is experiencing more years that are above average than it did in the past. For example, since 2000, Forest County has experienced only five years with below-average temperatures. Similarly, if we rank the top ten warmest years in Forest County since 1895 (black circles on the above chart), seven have occurred since 2000, with 1998 also in the top ten. The top ten coldest years (black squares) are a bit more spread out over time, with nine of the top ten years occurring before 2000.

On the annual timescale, precipitation has been increasing at a rate of 0.28″ per decade since 1950, which means an increase of one inch every 43 years. At the seasonal level, spring is the season of largest increase in precipitation in terms of inches per decade (0.17”/decade), but fall is the season with the largest percentage increase from average annual precipitation in the early 1950s (18 percent). Conversely, summers have been trending drier since 1950 (-0.12″/decade).

Looking at the full record from 1895 to 2025, annual precipitation has increased overall (one inch approximately every 30 years). However, unlike the top ten warmest years on record, the top ten wettest years on record are not clustered towards more-recent years. This mix of wet and dry years is normal within a long-term trend. Since 2000, for example, the county has had four of its top-ten wettest years on record, but it has also seen ten years with below-average precipitation. This year-to-year variability in annual precipitation points to the usefulness of long-term data sets when looking at climate trends.

Despite being one of Wisconsin’s most northern counties, Forest County is no stranger to sweltering summer heat, where daytime temperatures can top 90°F or even 100°F. But when are these hot days most likely to occur in Forest County? The State Climatology Office analyzed the likelihood of a “hot day” (daily high temperature ≥ 90°F) or “warm night” (daily low temperature ≥ 70°F) occurring between two calendar dates using historical measured temperature data from NOAA stations in Forest County. Based on this analysis, hot days have occurred most frequently between July 11 to 20. Warm nights have been the most common from July 1 to 10. Over the past 20 years (2006-2025), Forest County experiences, on average, three hot days per year. Warm nights are less common, with one warm night occurring per every two years.

Have Forest County summers been getting hotter? Since 1950, summertime average temperatures have warmed by about 2°F, but have not warmed as much compared to other seasons in Forest County. Summertime low temperatures have warmed by approximately 3°F since 1950.  By comparison, summer high temperatures in Forest County have not warmed as much (<1°F). You can read more about trends in summertime temperatures in Wisconsin in this blog post.

Forest County can get quite chilly once winter rolls around! Some of our coldest days of the year in Wisconsin are when the overnight low temperatures dip below 0°F. The State Climatology Office performed an analysis on the likelihood of a “very cold day” (daily high temperature ≤ 10°F) or “very cold night” (daily low temperature ≤ 0°F) occurring between two calendar dates using historical measured temperature data from NOAA stations in Forest County. Based on this analysis, very cold days and nights have occurred most frequently between January 21 to 31. Over the past 20 years (2006-2025), Forest County experienced, on average, 14 very cold days per year and 51 very cold nights per year.

Across all four seasons, winter has warmed the most in Forest County since 1950, a trend that holds true across most of Wisconsin. Since 1950, average winter temperatures in Forest County have warmed by about 5°F. Over this same time period, low temperatures in winter have warmed a bit more than the average temperatures (about 7°F).

Heavy precipitation days, which for this publication refers to a one-day liquid precipitation total of two inches or more, can impact Forest County at all times of the year. Extreme precipitation in the winter is measured by the amount of liquid that would be present if you melted down all of the snow that fell that day. The vast majority of these heavy precipitation days (79 percent) have occurred from June through September. July is the month that has historically had the most heavy precipitation days in Forest County. In general, summer is the wettest season in Forest County, with winter being the driest season. Over the past 20 years (2006-2025), Forest County experienced, on average, three heavy precipitation days per decade.

Future climate projections from the Wisconsin Initiative on Climate Change Impacts (WICCI) indicate that by mid-century (2041-2060), under a moderate greenhouse gas emissions scenario, average annual temperatures in Forest County will continue to increase by approximately 4°F compared to recent averages. Winter is projected to continue to be the season of the largest temperature increase (about 5°F). The number of nights where temperatures drop below 0°F is expected to decrease as winters warm (15-20 per year), and the number of nights in summer with temperatures staying above 70°F is expected to increase. The frequency of days that top 90°F is projected to increase with a warming climate to 10-15 days per year.

Annual precipitation is expected to increase by around five percent by mid-century, according to WICCI projections. Winter and spring are projected to be the seasons of greatest precipitation increase in Forest County (about 10%), with summers projected to be 5% drier by mid-century. Despite projections for drier summers, the frequency of heavy precipitation days (two inches or more) is projected to increase by mid-century. 

To explore more climate projections from WICCI and learn more about future climate modeling, please visit this website.

The data in this publication are a snapshot of the historical climate data for Forest County. If you have questions about this publication or would like more data on a topic, please contact the Wisconsin State Climatology Office. 

For more information about how climate affects your farm, community, health, and livelihood, please check out resources from the Division of Extension and the Wisconsin Initiative on Climate Change Impacts. 

Daily data from meteorological stations were used in order to summarize the frequency of extreme heat, cold, and precipitation events in Forest County. Due to large gaps in the data at the NWS COOP stations in Forest County, data from the following nearby stations were included in the analyses:

• COOP station in Eagle River, WI (Vilas County)
• COOP station in Caspian, MI (Iron County)

The data source used for the analyses of annual and seasonal trends in temperature and precipitation was NCEI Climate at a Glance, which summarizes data at the county level using the nClimGrid dataset. The nClimGrid dataset is a gridded meteorological dataset, which estimates temperature and precipitation “on a grid” by statistically interpolating between meteorological stations in the county and adjacent to the county. Thus, nClimGrid is using measured data to estimate conditions at locations within the county not directly by a meteorological station, which helps paint a more complete picture of county-level averages and trends.