DAILY INSOLATION


 (Btu/hr/ft2) on a South-Facing
Roof for Various Angles with Horizontal



40o N Latitude
0o
30o
40o
50o
60o
90o
Sept 21
1788
2210
2228
2182
2074
1416
Oct 21
1348
1962
2060
2098
2074
7654
Nov 21
942
1636
1778
1870
1908
1686
Dec 21
782
1480
1634
1740
1796
1646
Jan 21
948
1660
1810
1906
1944
1726
Feb 21
1414
2060
2162
2202
2176
1730
Mar 21
1852
2308
2330
2284
2174
1484
Apr 21
2274
2412
2320
2168
1956
1022
May 21
2552
2442
2264
2040
1760
724
Jun 21
2648
2434
2224
1974
1670
610
Jul 21
2534
2409
2230
2006
1728
702
Aug 21
2244
2354
2258
2104
1894
978



48o N Latitude
0o
30o
40o
50o
60o
90o
Sept 21
1522
2102
2118
2070
1966
1546
Oct 21
1022
1774
1860
1890
1866
1626
Nov 21
596
1336
1448
1518
1544
1442
Dec 21
446
1136
1250
1326
1364
1304
Jan 21
596
1360
1478
1550
1578
1478
Feb 21
1080
1880
1972
2024
1978
1720
Mar 21
1578
2208
2228
2182
2074
1632
Apr 21
2106
2358
2266
2114
1902
1262
May 21
2482
2418
2234
2010
1728
982
Jun 21
2626
2420
2204
1950
1644
874
Jul 21
2474
2386
2200
1974
1694
956
Aug 21
2086
2300
2200
2046
1836
1208




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