Precipitation

Connecticut sees a fairly even precipitation pattern with rainfall/snowfall spread throughout the 12 months.^[8] Connecticut averages 56% of possible sunshine (higher than the U.S. national average), averaging 2,400 hours of sunshine annually.^[9] On average, about one third of days in the state see some amount of precipitation each year.^[8] Occasionally, some months may see extremes in precipitation, either much higher or lower than normal. There have been several floods throughout Connecticut's history.

Early spring can range from slightly cool (40s to low 50s F) to warm (65 to 70 F), while mid and late spring (late April/May) is warm. By late May, the building Bermuda High creates a southerly flow of warm and humid tropical air, bringing hot weather conditions throughout the state. Average highs are 81 °F (27 °C) in New London and 85 °F (29 °C) in Windsor Locks at the peak of summer in late July. On occasion, heat waves with highs from 90 to 100 °F (38 °C) occur across Connecticut. Connecticut's record high temperature is 106 °F (41 °C) which occurred in Danbury on July 15, 1995.^{[8][10][11] [12]} Although summers are sunny in Connecticut, quick moving summer thunderstorms can bring brief downpours with thunder and lightning. Occasionally these thunderstorms can be severe, and the state usually averages one tornado per year.^[13] During hurricane season, the remains of tropical cyclones occasionally affect the region, though a direct hit is rare. Some notable hurricanes to impact the state include the 1938 New England hurricane, Hurricane Carol in 1954, Hurricane Sandy in 2012, and Hurricane Isaias in 2020.^[14][15]

Weather commonly associated with the fall season typically begins in October and lasts to the first days of December. Daily high temperatures in October and November range from the 50s to 60s (Fahrenheit) with nights in the 40s and upper 30s. Colorful foliage begins across northern parts of the state in early October and moves south and east reaching southeast Connecticut by early November. Far southern and coastal areas, however, have more oak and hickory trees (and fewer maples) and are often less colorful than areas to the north. By December daytime highs are in the 40s °F for much of the state, and average overnight lows are below freezing.

Winters (December through mid-March) are generally cold from south to north in Connecticut. The coldest month (January) has average high temperatures ranging from 38 °F (3 °C) in the coastal lowlands to 33 °F (1 °C) in the inland and northern portions on the state. The lowest temperature recorded in Connecticut is −32 °F (−36 °C) which has been observed twice: in Falls Village on February 16, 1943, and in Coventry on January 22, 1961.^[12] The average yearly snowfall ranges from about 60 inches (1,500 mm) in the higher elevations of the northern portion of the state to only 20–25 inches (510–640 mm) along the southeast coast of Connecticut (Branford to Groton). Generally, any locale north or west of Interstate 84 receives the most snow, during a storm, and throughout the season. Most of Connecticut has less than 60 days of snow cover. Snow usually falls from late November to late March in the northern part of the state, and from early December to mid-March in the southern and coastal parts of the state. During winter, on occasion Connecticut is subject to snowstorms which can bring one to two feet of snow on rare occasion, or heavy rain and tidal flooding. At times there has been some damage along the coast. ^[8][16] Ice storms also occur on occasion, such as the Southern New England ice storm of 1973 and the December 2008 Northeastern United States ice storm. These storms can cause widespread power outages and damage.

Climate data

Flora

Forests consist of a mix of Northeastern coastal forests of Oak in southern areas of the state, to the upland New England-Acadian forests in the northwestern parts of the state. Mountain Laurel (Kalmia latifolia) is the state flower and is native to low ridges in several parts of Connecticut. Rosebay Rhododendron (Rhododendron maximum) is also native to eastern uplands of Connecticut and Pachaug State Forest is home to the Rhododendron Sanctuary Trail. Atlantic white cedar (Chamaecyparis thyoides), is found in wetlands in the southern parts of the state. Connecticut has one native cactus (Opuntia humifusa), found in sandy coastal areas and low hillsides. Several types of beach grasses and wildflowers are also native to Connecticut.^[33] Connecticut spans USDA Plant Hardiness Zones 5b to 7a. Coastal Connecticut is the broad transition zone where more southern and subtropical plants are cultivated. In some coastal communities, Magnolia grandiflora (southern magnolia), Crape Myrtles, scrub palms (Sabal minor), Needle Palms (Rhapidophyllum hystrix), and other broadleaved evergreens are cultivated in small numbers.^{[citation needed]}