BothFormations in the Okanagan Highlands formations represent upland lake systems thatwhich were surrounded by a warm temperate ecosystem<ref name="Pigg2018"/> with nearby volcanism<ref name="GCL2011">{{cite journal |last1=Archibald |first1=S. |last2=Greenwood |first2=D. |last3=Smith |first3=R. |last4=Mathewes |first4=R. |last5=Basinger |first5=J. |year=2011 |title=Great Canadian ''Lagerstätten'' 1. Early Eocene Lagerstätten of the Okanagan Highlands (British Columbia and Washington State) |journal=Geoscience Canada |volume=38 |issue=4 |pages=155–164}}</ref> dating from during and just after the early Eocene climatic optimum. The highlands likely had a [[Mesic habitat|mesic]] [[Microthermal|upper microthermal]] to [[mesothermal|lower mesothermal]] climate, in which winter temperatures rarely dropped low enough for snow, and which were seasonably equitable.<ref name="Greenwood2005"/> The paleoforest surrounding the lakes have been described as precursors to the modern [[temperate broadleaf and mixed forests]] of Eastern North America and Eastern Asia. Based on the fossil [[Biota (plant)|biota]]s the lakes were higher and cooler then the [[coeval]] coastal forests preserved in the [[Puget Group]] and [[Chuckanut Formation]] of Western Washington, which are described as [[Tropical forest|lowland tropical forest]] ecosystems. Estimates of the [[elevation|paleoelevation]] range between {{cvt|0.7-1.2|km|mi}} higher than the coastal forests. This is consistent with the paleoelevation estimates for the lake systems, which range between {{cvt|1.1-2.9|km|m}}, which is similar to the modern elevation {{cvt|0.8|km|mi}}, but higher.<ref name="Greenwood2005"/>
Estimates of the [[Climate|mean annual temperature]] have been derived from [[Paleothermometer#CLAMP (Climate leaf analysis multivariate program)|climate leaf analysis multivariate program (CLAMP)]] analysis and [[Paleothermometer#Leaf margin analysis|leaf margin analysis (LMA)]] of both the Princeton and Republic paleofloras. The CLAMP results after multiple linear regressions for Republic gave a mean annual temperature of approximately {{cvt|8.0|C|F}}, while the LMA gave {{cvt|9.2|±|2.0|C|F}}. Princeton's multiple linear regression CLAMP results gave a slightly lower {{cvt|5.1|C|F}}, and the LMA returned a mean annual temperature of {{cvt|5.1|±|2.2|C|F}}. This is lower than the mean annual temperature estimates given for the coastal Puget Group, which is estimated to have been between {{cvt|15–18.6|C|F}}. The bioclimatic analysis for Republic and Princeton suggest mean annual precipitation amounts of {{cvt|115|±|39|cm|in}} and {{cvt|114|±|42|cm|in}} respectively.<ref name="Greenwood2005">{{cite journal |last1=Greenwood |first1=D.R. |last2=Archibald |first2=S.B. |last3=Mathewes |first3=R.W |last4=Moss |first4=P.T. |year=2005 |title=Fossil biotas from the Okanagan Highlands, southern British Columbia and northeastern Washington State: climates and ecosystems across an Eocene landscape |journal=Canadian Journal of Earth Sciences |volume=42 |issue=2 |pages=167–185|bibcode=2005CaJES..42..167G |doi=10.1139/e04-100}}</ref>
