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Delta Junction
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Delta Junction clear sky chart from 2005-11-06 to 2024-11-05.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	11% 11% 5% 11% 7% 6% 6% 5% 6% 7% 24%	107024
	Night	7% 12% 5% 13% 7% 6% 6% 4 6% 7% 25%	100612
Transparency	Day	54% 10% 16% 15% 4	106690
	Night	54% 9% 15% 15% 6% 1	100593
Seeing	Day	15% 7% 18% 25% 23% 11%	18469
	Night	13% 6% 19% 31% 24% 6%	22795

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	1 11% 7% 12% 6% 4 4 2 5% 7% 40%	1110
	11th to 20th	Day	2 12% 6% 12% 7% 7% 6% 5% 7% 8% 29%	1258
	21st to end	Day	3 8% 4 13% 10% 8% 8% 4 7% 9% 28%	1880
February	1st to 10th	Day	2 9% 4 14% 7% 7% 6% 6% 6% 8% 31%	1149
	11th to 20th	Day	2 15% 7% 12% 7% 6% 6% 4 7% 11% 23%	1441
	21st to end	Day	2 13% 6% 13% 9% 9% 6% 3 6% 6% 26%	1276
March	1st to 10th	Day	2 7% 7% 16% 10% 8% 5% 4 7% 7% 26%	3046
	11th to 20th	Day	2 10% 5% 14% 10% 8% 8% 5% 5% 7% 24%	3287
	21st to end	Day	4 11% 4 12% 8% 7% 6% 4 6% 7% 31%	4091
April	1st to 10th	Day	3 14% 5% 10% 6% 7% 7% 5% 7% 8% 26%	2432
	11th to 20th	Day	4 11% 4 9% 7% 6% 5% 4 7% 7% 36%	2607
	21st to end	Day	4 10% 4 9% 7% 6% 6% 5% 7% 7% 35%	2850
May	1st to 10th	Day	6% 16% 5% 12% 8% 7% 7% 5% 7% 7% 20%	5121
	11th to 20th	Day	8% 9% 3 9% 6% 6% 5% 5% 7% 9% 31%	5330
	21st to end	Day	14% 11% 4 10% 6% 6% 6% 5% 6% 7% 24%	6310
June	1st to 10th	Day	12% 9% 4 10% 7% 7% 8% 6% 9% 9% 21%	3610
	11th to 20th	Day	15% 9% 3 9% 7% 6% 7% 6% 7% 8% 24%	3667
	21st to end	Day	17% 7% 3 8% 6% 6% 7% 5% 8% 9% 24%	3743
July	1st to 10th	Day	23% 13% 4 10% 6% 6% 5% 4 6% 6% 17%	6020
	11th to 20th	Day	14% 9% 4 10% 6% 6% 6% 5% 7% 8% 26%	5733
	21st to end	Day	19% 9% 4 8% 5% 4 5% 4 7% 8% 26%	5993
August	1st to 10th	Day	20% 12% 4 8% 6% 6% 5% 4 6% 6% 24%	5059
	11th to 20th	Day	17% 10% 4 10% 7% 6% 6% 5% 6% 8% 19%	4727
	21st to end	Day	19% 14% 5% 12% 6% 6% 6% 4 5% 6% 17%	4863
September	1st to 10th	Day	15% 11% 5% 10% 7% 6% 6% 4 6% 7% 22%	2470
	11th to 20th	Day	21% 12% 4 9% 7% 5% 5% 4 6% 6% 22%	2210
	21st to end	Day	16% 15% 4 9% 6% 7% 6% 6% 5% 6% 21%	2090
October	1st to 10th	Day	11% 16% 5% 10% 4 4 5% 4 5% 7% 29%	2980
	11th to 20th	Day	6% 16% 6% 18% 8% 6% 5% 3 4 5% 22%	2834
	21st to end	Day	8% 17% 9% 17% 8% 6% 5% 4 4 6% 18%	2447
November	1st to 10th	Day	6% 19% 7% 10% 7% 8% 5% 4 6% 9% 20%	1255
	11th to 20th	Day	5% 18% 6% 15% 10% 7% 4 3 6% 6% 20%	950
	21st to end	Day	9% 9% 6% 12% 9% 6% 5% 6% 7% 8% 22%	846
December	1st to 10th	Day	7% 11% 6% 9% 8% 8% 6% 5% 7% 9% 23%	570
	11th to 20th	Day	3 14% 6% 15% 7% 7% 5% 6% 7% 10% 21%	724
	21st to end	Day	2 8% 5% 12% 7% 8% 7% 5% 8% 10% 29%	1045
January	1st to 10th	Night	1 8% 6% 14% 6% 6% 5% 4 5% 7% 37%	5874
	11th to 20th	Night	2 12% 5% 14% 7% 6% 6% 5% 7% 8% 28%	5650
	21st to end	Night	3 10% 4 14% 8% 6% 6% 5% 7% 9% 27%	5768
February	1st to 10th	Night	2 10% 4 10% 7% 6% 5% 6% 7% 9% 33%	3031
	11th to 20th	Night	2 11% 5% 14% 7% 6% 5% 5% 6% 8% 29%	2625
	21st to end	Night	2 12% 5% 15% 10% 8% 7% 4 5% 5% 26%	2178
March	1st to 10th	Night	2 9% 8% 17% 10% 7% 6% 3 4 6% 28%	3809
	11th to 20th	Night	2 10% 6% 19% 10% 7% 5% 3 5% 6% 26%	3671
	21st to end	Night	2 11% 5% 10% 5% 6% 6% 5% 8% 8% 32%	3540
April	1st to 10th	Night	4 12% 5% 11% 7% 5% 5% 6% 8% 9% 28%	1748
	11th to 20th	Night	5% 13% 4 9% 5% 5% 6% 5% 7% 7% 34%	1522
	21st to end	Night	5% 9% 4 8% 7% 4 5% 5% 6% 9% 39%	1330
May	1st to 10th	Night	9% 15% 6% 13% 7% 8% 7% 5% 6% 6% 17%	1843
	11th to 20th	Night	8% 11% 4 10% 8% 5% 7% 6% 8% 8% 26%	1565
	21st to end	Night	14% 11% 3 10% 5% 6% 7% 3 6% 8% 26%	1274
June	1st to 10th	Night	11% 9% 4 10% 7% 7% 8% 6% 9% 10% 19%	570
	11th to 20th	Night	15% 7% 4 8% 9% 5% 6% 7% 7% 8% 25%	508
	21st to end	Night	12% 9% 5% 11% 4 6% 6% 6% 10% 12% 21%	434
July	1st to 10th	Night	23% 9% 3 11% 7% 5% 6% 5% 7% 7% 17%	950
	11th to 20th	Night	19% 9% 4 10% 6% 6% 6% 5% 6% 9% 22%	1235
	21st to end	Night	18% 12% 3 9% 5% 6% 4 5% 8% 8% 22%	1564
August	1st to 10th	Night	24% 11% 4 7% 5% 4 4 3 6% 7% 24%	1880
	11th to 20th	Night	23% 13% 5% 10% 7% 6% 6% 3 5% 5% 18%	2111
	21st to end	Night	22% 15% 4 11% 6% 5% 5% 3 5% 6% 19%	2803
September	1st to 10th	Night	14% 10% 3 10% 6% 6% 6% 5% 7% 7% 24%	1710
	11th to 20th	Night	19% 13% 3 10% 6% 5% 5% 4 5% 5% 23%	1970
	21st to end	Night	18% 16% 6% 11% 5% 6% 5% 3 5% 5% 20%	2090
October	1st to 10th	Night	12% 17% 5% 11% 6% 5% 6% 5% 6% 7% 21%	3987
	11th to 20th	Night	7% 17% 7% 15% 8% 6% 4 4 5% 6% 21%	4094
	21st to end	Night	7% 18% 8% 13% 6% 6% 6% 4 5% 6% 20%	5111
November	1st to 10th	Night	7% 18% 6% 12% 7% 6% 5% 4 6% 8% 22%	2922
	11th to 20th	Night	4 17% 7% 18% 9% 6% 5% 4 5% 6% 19%	3230
	21st to end	Night	5% 14% 5% 12% 8% 6% 8% 5% 7% 10% 19%	3313
December	1st to 10th	Night	6% 12% 6% 12% 8% 7% 6% 5% 7% 8% 23%	3610
	11th to 20th	Night	3 13% 7% 16% 9% 8% 6% 5% 7% 8% 17%	4470
	21st to end	Night	2 10% 6% 14% 8% 7% 6% 4 7% 9% 28%	6622

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	43% 8% 15% 20% 12% 2	1110
	11th to 20th	Day	47% 11% 15% 17% 9% 1	1270
	21st to end	Day	49% 8% 11% 16% 9% 7%	1880
February	1st to 10th	Day	46% 7% 9% 17% 17% 3	1149
	11th to 20th	Day	51% 9% 16% 15% 9%	1448
	21st to end	Day	55% 8% 11% 14% 11% 1	1276
March	1st to 10th	Day	53% 8% 9% 17% 13% 1	3046
	11th to 20th	Day	51% 9% 17% 14% 8%	3287
	21st to end	Day	46% 12% 18% 15% 8% 1	4091
April	1st to 10th	Day	50% 9% 18% 16% 6%	2432
	11th to 20th	Day	44% 9% 15% 23% 7% 2	2607
	21st to end	Day	42% 10% 15% 22% 11% 1	2850
May	1st to 10th	Day	55% 12% 13% 14% 5%	5121
	11th to 20th	Day	43% 11% 14% 26% 6% 1	5333
	21st to end	Day	53% 12% 14% 17% 5%	6311
June	1st to 10th	Day	53% 13% 18% 14% 2	3610
	11th to 20th	Day	54% 12% 16% 15% 4	3667
	21st to end	Day	53% 12% 19% 14% 2	3743
July	1st to 10th	Day	66% 8% 17% 8% 1	5926
	11th to 20th	Day	52% 9% 17% 21% 1	5632
	21st to end	Day	54% 9% 21% 15% 2	5804
August	1st to 10th	Day	60% 8% 19% 11% 3	5039
	11th to 20th	Day	59% 10% 17% 13% 1	4773
	21st to end	Day	67% 7% 19% 6%	4862
September	1st to 10th	Day	58% 13% 19% 10% 1	2470
	11th to 20th	Day	61% 9% 17% 12% 1	2210
	21st to end	Day	60% 10% 14% 14% 2	2090
October	1st to 10th	Day	54% 7% 13% 21% 5%	2980
	11th to 20th	Day	62% 9% 12% 16% 1	2834
	21st to end	Day	67% 6% 17% 10% 1	2447
November	1st to 10th	Day	58% 9% 16% 13% 4	1255
	11th to 20th	Day	63% 8% 12% 14% 3	950
	21st to end	Day	55% 8% 17% 15% 5%	846
December	1st to 10th	Day	52% 14% 12% 16% 6%	570
	11th to 20th	Day	52% 10% 16% 19% 4	726
	21st to end	Day	44% 9% 18% 18% 11% 1	1045
January	1st to 10th	Night	44% 10% 16% 21% 7% 1	5874
	11th to 20th	Night	47% 12% 18% 15% 8% 1	5700
	21st to end	Night	49% 7% 10% 16% 14% 4	5768
February	1st to 10th	Night	42% 8% 10% 17% 20% 2	3031
	11th to 20th	Night	48% 9% 15% 18% 9%	2629
	21st to end	Night	57% 7% 11% 15% 8% 1	2178
March	1st to 10th	Night	56% 7% 10% 16% 11% 1	3809
	11th to 20th	Night	55% 9% 14% 13% 8%	3673
	21st to end	Night	41% 15% 18% 14% 9% 1	3540
April	1st to 10th	Night	46% 10% 20% 17% 6% 1	1748
	11th to 20th	Night	45% 11% 15% 21% 7% 1	1522
	21st to end	Night	39% 10% 17% 23% 12%	1330
May	1st to 10th	Night	59% 12% 10% 14% 4 1	1843
	11th to 20th	Night	48% 13% 12% 21% 5%	1565
	21st to end	Night	50% 13% 14% 17% 7%	1274
June	1st to 10th	Night	50% 15% 17% 17% 1	570
	11th to 20th	Night	55% 9% 18% 16% 2	508
	21st to end	Night	50% 15% 20% 15%	434
July	1st to 10th	Night	63% 7% 20% 9% 1	935
	11th to 20th	Night	56% 10% 17% 16% 1	1213
	21st to end	Night	58% 8% 21% 12% 1	1514
August	1st to 10th	Night	58% 7% 20% 12% 3	1875
	11th to 20th	Night	67% 8% 12% 13%	2131
	21st to end	Night	67% 6% 17% 10%	2803
September	1st to 10th	Night	55% 12% 21% 11% 1	1710
	11th to 20th	Night	60% 10% 16% 13% 1	1970
	21st to end	Night	65% 8% 13% 12% 1	2090
October	1st to 10th	Night	60% 7% 12% 19% 2	3987
	11th to 20th	Night	63% 7% 12% 14% 3	4094
	21st to end	Night	63% 7% 17% 12% 2	5111
November	1st to 10th	Night	58% 10% 15% 14% 4	2922
	11th to 20th	Night	63% 8% 14% 12% 2	3230
	21st to end	Night	54% 10% 13% 17% 5%	3313
December	1st to 10th	Night	55% 11% 13% 16% 5%	3610
	11th to 20th	Night	56% 11% 14% 14% 4	4467
	21st to end	Night	48% 9% 15% 16% 11% 1	6622

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	8% 9% 21% 31% 22% 9%	90
	11th to 20th	Day	4 7% 22% 47% 16% 4	90
	21st to end	Day	9% 5% 15% 32% 25% 14%	208
February	1st to 10th	Day	6% 8% 19% 28% 20% 18%	284
	11th to 20th	Day	8% 10% 28% 32% 17% 5%	365
	21st to end	Day	7% 11% 25% 32% 18% 7%	307
March	1st to 10th	Day	6% 6% 24% 30% 25% 9%	370
	11th to 20th	Day	6% 8% 23% 29% 22% 12%	370
	21st to end	Day	8% 8% 25% 29% 21% 9%	568
April	1st to 10th	Day	7% 10% 26% 31% 20% 6%	632
	11th to 20th	Day	9% 8% 25% 28% 22% 9%	640
	21st to end	Day	8% 5% 20% 31% 29% 8%	650
May	1st to 10th	Day	11% 10% 24% 24% 25% 6%	653
	11th to 20th	Day	13% 6% 22% 24% 23% 12%	675
	21st to end	Day	17% 8% 20% 23% 23% 8%	993
June	1st to 10th	Day	12% 6% 16% 26% 26% 14%	1060
	11th to 20th	Day	16% 5% 15% 22% 26% 17%	1060
	21st to end	Day	15% 4 12% 22% 30% 17%	1060
July	1st to 10th	Day	18% 4 14% 23% 28% 13%	1041
	11th to 20th	Day	21% 5% 16% 19% 25% 14%	870
	21st to end	Day	17% 4 14% 23% 25% 17%	833
August	1st to 10th	Day	24% 7% 15% 20% 21% 12%	676
	11th to 20th	Day	22% 7% 17% 25% 20% 9%	665
	21st to end	Day	25% 7% 15% 21% 22% 10%	748
September	1st to 10th	Day	19% 10% 15% 22% 21% 14%	680
	11th to 20th	Day	27% 7% 22% 22% 15% 7%	508
	21st to end	Day	24% 7% 16% 23% 17% 13%	390
October	1st to 10th	Day	21% 13% 21% 20% 16% 9%	390
	11th to 20th	Day	15% 8% 18% 26% 21% 11%	390
	21st to end	Day	16% 6% 18% 24% 27% 9%	429
November	1st to 10th	Day	15% 9% 15% 31% 21% 9%	315
	11th to 20th	Day	11% 12% 19% 23% 23% 11%	90
	21st to end	Day	10% 9% 28% 28% 18% 8%	90
December	1st to 10th	Day	11% 11% 19% 32% 20% 7%	90
	11th to 20th	Day	10% 10% 20% 42% 13% 4	90
	21st to end	Day	7% 9% 26% 30% 21% 6%	99
January	1st to 10th	Night	5% 5% 23% 33% 25% 8%	1050
	11th to 20th	Night	8% 7% 23% 40% 17% 5%	940
	21st to end	Night	9% 5% 21% 34% 26% 5%	944
February	1st to 10th	Night	5% 6% 25% 33% 24% 7%	850
	11th to 20th	Night	6% 9% 29% 37% 17% 3	834
	21st to end	Night	9% 6% 24% 37% 21% 4	703
March	1st to 10th	Night	5% 7% 19% 40% 27% 3	707
	11th to 20th	Night	6% 5% 18% 38% 29% 5%	624
	21st to end	Night	7% 7% 23% 33% 24% 6%	627
April	1st to 10th	Night	8% 5% 21% 39% 23% 4	570
	11th to 20th	Night	11% 7% 17% 35% 23% 6%	563
	21st to end	Night	8% 3 16% 31% 36% 6%	570
May	1st to 10th	Night	14% 5% 18% 28% 32% 3	349
	11th to 20th	Night	7% 9% 21% 33% 27% 3	187
	21st to end	Night	11% 8% 14% 34% 29% 4	206
June	1st to 10th	Night	12% 4 16% 31% 32% 5%	190
	11th to 20th	Night	18% 4 10% 26% 32% 11%	190
	21st to end	Night	16% 1 11% 29% 33% 10%	190
July	1st to 10th	Night	21% 3 12% 24% 31% 8%	185
	11th to 20th	Night	24% 6% 7% 23% 33% 7%	184
	21st to end	Night	20% 6% 10% 25% 30% 10%	208
August	1st to 10th	Night	26% 4 14% 23% 27% 6%	364
	11th to 20th	Night	25% 5% 17% 23% 23% 6%	515
	21st to end	Night	25% 5% 12% 21% 27% 10%	627
September	1st to 10th	Night	19% 5% 17% 24% 26% 8%	570
	11th to 20th	Night	25% 7% 17% 26% 21% 5%	570
	21st to end	Night	26% 5% 15% 22% 22% 9%	570
October	1st to 10th	Night	24% 8% 21% 25% 19% 4	790
	11th to 20th	Night	20% 6% 18% 27% 22% 7%	860
	21st to end	Night	15% 7% 18% 29% 25% 7%	946
November	1st to 10th	Night	16% 6% 17% 31% 25% 5%	854
	11th to 20th	Night	12% 6% 16% 32% 27% 7%	850
	21st to end	Night	11% 7% 21% 31% 23% 7%	905
December	1st to 10th	Night	11% 9% 21% 31% 21% 7%	1130
	11th to 20th	Night	10% 5% 22% 33% 24% 6%	1130
	21st to end	Night	8% 9% 19% 35% 23% 7%	1243

Page generated at 2024-11-02 22:11:26. Version ac07

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