{"metadata":{"title":"Chatham, MA Monthly Climate Normals","page_url":"https://plainclimate.com/city/chatham-ma","primary_station_id":"USC00191386","source":"NOAA 1991-2020 U.S. Climate Normals","source_url":"https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals","vintage":"2026-08-04","license":"CC0 1.0","license_url":"https://creativecommons.org/publicdomain/zero/1.0/","citation":"PlainClimate, \"Chatham, MA Climate Normals\". https://plainclimate.com/city/chatham-ma","row_count":12},"annual_summary":{"city_slug":"chatham-ma","ann_tavg":50.3,"ann_tmax":56.6,"ann_tmin":44.1,"ann_prcp":45.93,"ann_snow":24.5,"ann_htdd":5681.3,"ann_cldd":369.3,"frost_first":"11/15","frost_last":"04/05","growing_season":224,"warmest_month":7,"coldest_month":1,"wettest_month":12,"driest_month":7,"snowiest_month":2,"comfort_score":63},"data":[{"month":"January","month_number":1,"avg_temp_f":31.7,"avg_high_f":38.6,"avg_low_f":24.9,"precip_in":3.97,"snow_in":7.5,"heating_degree_days":1030.7,"cooling_degree_days":0,"days_with_precip":12.4,"days_with_snow":3.6,"days_freezing":23.4,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"February","month_number":2,"avg_temp_f":31.9,"avg_high_f":38.9,"avg_low_f":25,"precip_in":3.84,"snow_in":9.9,"heating_degree_days":925.4,"cooling_degree_days":0,"days_with_precip":10.9,"days_with_snow":3.9,"days_freezing":21.1,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"March","month_number":3,"avg_temp_f":36.9,"avg_high_f":43.1,"avg_low_f":30.7,"precip_in":4.71,"snow_in":3.8,"heating_degree_days":871.1,"cooling_degree_days":0,"days_with_precip":11.7,"days_with_snow":1.8,"days_freezing":15.9,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"April","month_number":4,"avg_temp_f":45.3,"avg_high_f":51.1,"avg_low_f":39.5,"precip_in":4.01,"snow_in":0.5,"heating_degree_days":591,"cooling_degree_days":0,"days_with_precip":11.5,"days_with_snow":0.2,"days_freezing":2.1,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"May","month_number":5,"avg_temp_f":53.9,"avg_high_f":59.7,"avg_low_f":48.1,"precip_in":3.3,"snow_in":0,"heating_degree_days":344.8,"cooling_degree_days":0.8,"days_with_precip":11,"days_with_snow":0,"days_freezing":0,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"June","month_number":6,"avg_temp_f":62.8,"avg_high_f":69,"avg_low_f":56.6,"precip_in":3.17,"snow_in":0,"heating_degree_days":98.6,"cooling_degree_days":32.6,"days_with_precip":9.6,"days_with_snow":0,"days_freezing":0,"days_90f_plus":0.1,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"July","month_number":7,"avg_temp_f":69.5,"avg_high_f":75.9,"avg_low_f":63.1,"precip_in":2.8,"snow_in":0,"heating_degree_days":7.9,"cooling_degree_days":147.4,"days_with_precip":8.2,"days_with_snow":0,"days_freezing":0,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"August","month_number":8,"avg_temp_f":69.4,"avg_high_f":75.8,"avg_low_f":62.9,"precip_in":3.2,"snow_in":0,"heating_degree_days":5.6,"cooling_degree_days":140.4,"days_with_precip":8.3,"days_with_snow":0,"days_freezing":0,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"September","month_number":9,"avg_temp_f":64.4,"avg_high_f":70.3,"avg_low_f":58.4,"precip_in":3.78,"snow_in":0,"heating_degree_days":65.6,"cooling_degree_days":46,"days_with_precip":8.7,"days_with_snow":0,"days_freezing":0,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"October","month_number":10,"avg_temp_f":54.9,"avg_high_f":61.1,"avg_low_f":48.7,"precip_in":4.31,"snow_in":0,"heating_degree_days":315.3,"cooling_degree_days":2.2,"days_with_precip":10.8,"days_with_snow":0,"days_freezing":0,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"November","month_number":11,"avg_temp_f":45.8,"avg_high_f":52,"avg_low_f":39.6,"precip_in":4.12,"snow_in":0.2,"heating_degree_days":576,"cooling_degree_days":0,"days_with_precip":10.6,"days_with_snow":0.2,"days_freezing":4.8,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null},{"month":"December","month_number":12,"avg_temp_f":37.6,"avg_high_f":44,"avg_low_f":31.2,"precip_in":4.72,"snow_in":2.6,"heating_degree_days":849.4,"cooling_degree_days":0,"days_with_precip":12.9,"days_with_snow":1.5,"days_freezing":15.8,"days_90f_plus":0,"humidity_pct":null,"wind_speed_mph":null,"clear_sky_pct":null,"overcast_pct":null}]}