Heat in the Field

Alhough several factors determine the risk of experiencing heat stress, ambient temperature has obviously important effects on rate of heat buildup and dissipation.  Below are monthly average temperatures in different parts of California with agricultural production.  Numbers are color-coded with respect to their potential contribution to heat stress.    Assuming a moderate to heavy work, their associated risks are:
High ( > 82 degrees),  Low ( < 70 degrees), or Moderate.
  • North Coast
  • North Central
  • Central Coast
  • South

    • North Coast

    Cloverdale (Sonoma County) CA.
    Located at about 38.81°N 123.00°W. Altitude about 101m / 331 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    57.4 61.7 64.0 70.2 77.5 84.9 90.7 90.0 86.2 77.9 64.9 57.2

    Healdsburg (Sonoma County) CA.
    Located at about 38.61°N 122.86°W. Altitude about 32m / 104 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    57.6 63.3 66.4 72.1 78.6 84.7 89.6 88.5 86.2 78.4 65.7 57.4

    Ukiah (Mendocino County) CA.
    Located at about 39.15°N 123.20°W. Altitude about 192m / 629 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    57.7
    61.7
    64.2
    69.8
    77.0
    84.9
    92.3
    91.6
    87.1
    77.4
    63.1
    56.7

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    North Central

    Marysville (Sacramento County)
    Located at about 39.15°N 121.60°W. Altitude about 17m / 55 feet above sea level.
    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec
    54.0
    60.3
    65.7
    72.9
    81.0
    89.4
    96.1
    94.3
    88.9
    78.8
    65.1
    54.9

    Modesto  (Stanislaus County) CA.
    Located at about 37.65°N 121.00°W. Altitude about 27m / 88 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    53.6
    61.9
    67.1
    73.8
    81.5
    88.9
    94.1
    92.3
    87.4
    78.3
    63.7
    53.2

    Coalinga  (Fresno County) CA.
    Located at about 36.15°N 120.35°W. Altitude about 204m / 669 feet above sea level
    Jan.
    Feb.
    Mar.
    Apr.
    May 
    Jun.
    Jul.
    Aug.
    Sept.
    Oct.
    Nov.
    Dec.
    57.2
    64.0
    69.1
    76.1
    85.5
    93.4
    98.8
    97.2
    91.6
    81.7
    67.1
    57.7

    Lemoore/Reeves  (Madera County) CA.
    Located at about 36.33°N 119.95°W. Altitude about 73m / 239 feet above sea level.
    Jan.
    Feb.
    Mar.
    Apr.
    May
    Jun.
    Jul.
    Aug.
    Sept.
    Oct.
    Nov.
    Dec.
    55.0
    63.0
    68.2 
    75.9
    85.3
    92.8
    98.4
    96.4
    90.5
    81.0
    65.8
    54.7

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    Central Coast

    Gilroy  (Santa Clara County) CA.
    Located at about 37.00°N 121.56°W.  Altitude about 59m / 193 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    59.2
    63.7
    66.4
    71.8
    77.5
    83.5
    88.2
    87.4
    85.3
    78.3
    66.6
    59.2

    King City (Monterey County) CA.
    Located at about 36.20°N 121.13°W.  Altitude about 97m / 318 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    62.2
    65.7
    67.8
    72.5
    77.0
    81.7
    84.2
    84.0
    83.5
    78.8
    68.2
    62.1

    Monterey  (Monterey County) CA.
    Located at about 36.60°N 121.87°W. Altitude about 50m / 164 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
    57.6
    59.2
    59.0
    60.1
    61.5
    64.8
    65.1
    65.5
    67.8
    66.0
    64.2
    60.6
    62.6

    Watsonville,  (Santa Cruz County) CA.
    Located at about 36.93°N 121.76°W.  Altitude about 29m / 95 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    60.4
    62.4
    63.1
    66.2
    67.8
    70.2
    71.2
    71.8
    73.2
    71.8
    65.7
    60.3

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    South

    Bakersfield Meadows  (Kern County) CA.
    Located at about 35.41°N 119.05°W.  Altitude about 150m / 492 feet above sea level.
    Jan. Feb. Mar. Apr. May  Jun. Jul. Aug. Sept. Oct. Nov. Dec.
    56.8 63.9 68.9 75.7 84.6 92.3 98.4 96.4 90.0 80.6 66.7 56.5

    Blythe  (Riverside County) CA.
    Located at about 33.61°N 114.72°W.   about 118m / 387 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    65.5 71.8 77.4 86.2 94.1 104.0 108.0 106.2 101.3 90.0 75.6 66.6

    Corcoran  (Kings County) CA.
    Located at about 36.10°N 119.56°W.  Altitude about 61m / 200 feet above sea level.
    Jan. Feb. Mar. Apr. May  Jun. Jul. Aug. Sept. Oct. Nov. Dec.
    54.1 62.2 68.2  76.3 85.6 93.4 99.0 97.0 90.9 81.1 65.8 54.1

    El Centro (Imperial County) CA.
    Located at about 32.76°N 115.56°W.  Altitude about -9m / -29 feet above sea level.
    Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    69.8 74.5 79.0 85.6 94.3 103.5 107.4 106.0 100.9 91.0 78.3 69.4

    Wasco (Kern County) CA.
    Located at about 35.60°N 119.33°W.  Altitude about 105m / 344 feet above sea level.
    Jan. Feb. Mar. Apr. May  Jun. Jul. Aug. Sept. Oct. Nov. Dec.
    55.9 64.2 70.0 77.9 86.4 94.5 99.5 97.7 91.9 82.0 67.1 55.9

    source:  U.S. National Weather Service

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