Deer Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Deer Park clear sky chart from 2005-11-06 to 2024-12-06.

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% 6% 2 7% 5% 5% 5% 4 6% 8% 41%	100826
	Night	12% 6% 2 6% 4 4 4 4 6% 8% 44%	98840
Transparency	Day	39% 6% 11% 18% 18% 8%	104696
	Night	36% 6% 12% 17% 19% 9%	103108
Seeing	Day	15% 8% 21% 24% 21% 11%	14444
	Night	14% 7% 22% 30% 22% 6%	24389

By Month

Percentage Cloud Cover SE (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	15% 7% 2 5% 3 3 4 4 6% 9% 43%	3071
	11th to 20th	Day	10% 6% 2 4 3 3 4 3 5% 5% 56%	3160
	21st to end	Day	23% 7% 3 6% 3 3 3 2 3 5% 41%	3476
February	1st to 10th	Day	17% 8% 3 7% 4 5% 5% 4 4 5% 39%	1900
	11th to 20th	Day	19% 6% 2 5% 4 3 3 3 5% 7% 43%	1848
	21st to end	Day	16% 9% 2 8% 4 4 4 3 5% 7% 39%	1570
March	1st to 10th	Day	19% 11% 4 9% 4 4 4 4 4 6% 32%	3120
	11th to 20th	Day	14% 6% 3 7% 4 4 4 4 5% 8% 40%	3305
	21st to end	Day	15% 5% 2 7% 5% 5% 4 4 5% 6% 42%	4165
April	1st to 10th	Day	12% 6% 2 5% 6% 4 5% 4 6% 7% 43%	2280
	11th to 20th	Day	13% 6% 3 6% 4 5% 4 4 7% 7% 42%	2254
	21st to end	Day	7% 5% 3 5% 5% 4 4 3 5% 7% 51%	2280
May	1st to 10th	Day	9% 5% 2 6% 6% 5% 5% 5% 7% 9% 42%	3765
	11th to 20th	Day	15% 6% 2 7% 5% 4 4 4 5% 7% 41%	3921
	21st to end	Day	6% 4 2 6% 6% 5% 6% 4 7% 10% 45%	4476
June	1st to 10th	Day	9% 7% 3 7% 6% 7% 7% 5% 8% 9% 33%	2470
	11th to 20th	Day	6% 5% 2 6% 7% 7% 7% 6% 8% 9% 37%	2470
	21st to end	Day	7% 6% 3 9% 7% 7% 7% 7% 8% 10% 29%	2470
July	1st to 10th	Day	7% 7% 3 9% 7% 8% 9% 6% 10% 11% 23%	4096
	11th to 20th	Day	7% 6% 3 9% 8% 8% 8% 6% 9% 10% 27%	3800
	21st to end	Day	7% 6% 3 9% 8% 8% 8% 7% 9% 13% 21%	4118
August	1st to 10th	Day	3 3 1 5% 4 5% 6% 5% 8% 11% 50%	3785
	11th to 20th	Day	6% 4 2 6% 5% 6% 6% 5% 7% 10% 43%	3729
	21st to end	Day	7% 4 2 8% 6% 6% 6% 5% 7% 9% 38%	4180
September	1st to 10th	Day	9% 7% 3 8% 7% 5% 6% 4 6% 8% 37%	2280
	11th to 20th	Day	12% 7% 2 7% 5% 5% 4 4 6% 7% 42%	2116
	21st to end	Day	8% 5% 2 6% 4 5% 4 3 5% 6% 52%	2090
October	1st to 10th	Day	8% 3 2 6% 4 4 4 3 5% 6% 56%	2090
	11th to 20th	Day	9% 4 2 5% 3 3 4 3 5% 6% 54%	2014
	21st to end	Day	11% 4 1 5% 3 3 3 3 4 6% 56%	2090
November	1st to 10th	Day	10% 4 2 5% 4 3 3 3 4 5% 56%	1805
	11th to 20th	Day	14% 5% 2 3 3 2 3 2 4 5% 56%	1800
	21st to end	Day	12% 7% 2 6% 3 4 3 4 5% 7% 47%	1800
December	1st to 10th	Day	14% 7% 3 6% 4 4 4 3 5% 6% 45%	1755
	11th to 20th	Day	15% 9% 3 8% 4 3 4 3 4 5% 43%	2153
	21st to end	Day	16% 9% 2 5% 4 4 4 4 5% 7% 40%	3124
January	1st to 10th	Night	17% 7% 2 4 4 3 3 3 5% 6% 46%	3856
	11th to 20th	Night	14% 8% 2 4 2 3 2 2 4 5% 52%	3800
	21st to end	Night	24% 10% 2 5% 3 3 2 2 4 4 42%	4180
February	1st to 10th	Night	15% 8% 3 5% 4 4 4 4 4 8% 42%	2280
	11th to 20th	Night	20% 7% 2 5% 3 3 3 3 5% 5% 44%	2218
	21st to end	Night	17% 9% 3 7% 5% 4 4 3 4 5% 39%	1884
March	1st to 10th	Night	22% 12% 4 7% 4 4 4 3 4 4 33%	3733
	11th to 20th	Night	13% 8% 3 7% 4 5% 5% 3 6% 7% 40%	3680
	21st to end	Night	15% 6% 2 5% 4 4 4 3 4 6% 46%	3466
April	1st to 10th	Night	13% 6% 2 6% 4 4 3 4 6% 7% 45%	1900
	11th to 20th	Night	13% 5% 3 6% 4 4 3 3 5% 7% 46%	1875
	21st to end	Night	7% 4 2 4 3 3 4 3 4 7% 59%	1900
May	1st to 10th	Night	10% 7% 3 6% 5% 4 4 4 6% 8% 44%	3130
	11th to 20th	Night	13% 6% 3 7% 5% 4 4 4 5% 7% 42%	2957
	21st to end	Night	7% 5% 2 6% 4 4 5% 4 8% 11% 43%	3079
June	1st to 10th	Night	8% 6% 3 7% 5% 5% 5% 4 9% 13% 37%	1710
	11th to 20th	Night	4 4 1 5% 5% 5% 5% 6% 7% 12% 45%	1710
	21st to end	Night	5% 7% 2 6% 5% 4 6% 6% 8% 13% 38%	1710
July	1st to 10th	Night	7% 6% 3 8% 5% 5% 7% 6% 10% 13% 32%	2859
	11th to 20th	Night	4 5% 2 6% 6% 6% 6% 5% 9% 13% 38%	3160
	21st to end	Night	5% 6% 3 8% 7% 7% 7% 7% 10% 12% 27%	3435
August	1st to 10th	Night	2 3 1 4 4 5% 5% 5% 8% 14% 49%	3144
	11th to 20th	Night	4 3 2 6% 5% 5% 6% 5% 8% 11% 46%	3100
	21st to end	Night	5% 5% 2 6% 5% 7% 7% 5% 8% 11% 40%	3476
September	1st to 10th	Night	9% 6% 2 8% 6% 5% 6% 6% 7% 9% 36%	1900
	11th to 20th	Night	10% 6% 3 6% 5% 4 5% 4 6% 7% 44%	2042
	21st to end	Night	8% 5% 2 5% 4 5% 4 4 7% 7% 50%	2090
October	1st to 10th	Night	8% 4 2 5% 3 4 4 3 5% 7% 55%	2090
	11th to 20th	Night	9% 4 2 3 3 3 3 2 4 6% 61%	2161
	21st to end	Night	12% 5% 2 4 3 2 3 2 4 6% 57%	2508
November	1st to 10th	Night	9% 5% 2 5% 4 4 3 2 4 6% 56%	2491
	11th to 20th	Night	13% 6% 2 4 3 3 3 3 5% 6% 53%	2600
	21st to end	Night	12% 6% 2 4 3 3 4 4 5% 6% 50%	2600
December	1st to 10th	Night	13% 6% 3 5% 4 3 3 3 5% 7% 48%	2542
	11th to 20th	Night	16% 8% 3 5% 4 4 4 3 5% 5% 45%	3042
	21st to end	Night	16% 9% 2 6% 4 4 4 3 4 5% 42%	4532

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	38% 3 6% 19% 24% 10%	3072
	11th to 20th	Day	31% 3 5% 21% 30% 10%	3160
	21st to end	Day	48% 3 4 15% 21% 9%	3476
February	1st to 10th	Day	48% 3 8% 12% 19% 10%	1900
	11th to 20th	Day	42% 3 6% 16% 23% 10%	1858
	21st to end	Day	46% 4 8% 15% 17% 11%	1570
March	1st to 10th	Day	53% 5% 9% 14% 15% 6%	3120
	11th to 20th	Day	42% 5% 8% 20% 19% 6%	3305
	21st to end	Day	42% 5% 8% 16% 20% 9%	4165
April	1st to 10th	Day	39% 6% 7% 19% 19% 11%	2280
	11th to 20th	Day	40% 5% 7% 18% 21% 9%	2254
	21st to end	Day	32% 5% 9% 21% 25% 8%	2280
May	1st to 10th	Day	35% 9% 11% 24% 18% 4	3800
	11th to 20th	Day	41% 6% 10% 21% 19% 2	3925
	21st to end	Day	33% 6% 12% 32% 14% 2	4489
June	1st to 10th	Day	44% 8% 13% 23% 10% 2	2470
	11th to 20th	Day	39% 9% 15% 21% 12% 4	2470
	21st to end	Day	46% 9% 18% 17% 10% 1	2470
July	1st to 10th	Day	48% 13% 22% 13% 4	4031
	11th to 20th	Day	45% 13% 28% 11% 3 1	3737
	21st to end	Day	48% 15% 19% 14% 4	3987
August	1st to 10th	Day	26% 8% 16% 27% 22% 1	3773
	11th to 20th	Day	33% 8% 15% 25% 17% 1	3765
	21st to end	Day	40% 10% 18% 15% 15% 2	4179
September	1st to 10th	Day	44% 8% 14% 16% 13% 5%	2280
	11th to 20th	Day	41% 7% 11% 16% 18% 7%	2116
	21st to end	Day	33% 5% 11% 22% 20% 9%	2090
October	1st to 10th	Day	28% 2 8% 11% 22% 30%	3480
	11th to 20th	Day	19% 3 5% 16% 25% 33%	3332
	21st to end	Day	22% 3 4 12% 40% 18%	3428
November	1st to 10th	Day	32% 3 6% 20% 25% 14%	1805
	11th to 20th	Day	32% 3 6% 16% 28% 16%	1800
	21st to end	Day	37% 4 7% 16% 23% 12%	1800
December	1st to 10th	Day	40% 4 9% 17% 22% 8%	1755
	11th to 20th	Day	45% 2 7% 14% 23% 9%	2150
	21st to end	Day	44% 4 6% 21% 20% 6%	3124
January	1st to 10th	Night	39% 3 7% 13% 29% 9%	3856
	11th to 20th	Night	35% 2 5% 18% 27% 12%	3800
	21st to end	Night	48% 2 4 14% 25% 7%	4180
February	1st to 10th	Night	42% 3 8% 16% 20% 11%	2280
	11th to 20th	Night	44% 4 5% 13% 22% 12%	2219
	21st to end	Night	46% 5% 8% 14% 13% 13%	1884
March	1st to 10th	Night	55% 5% 8% 12% 13% 7%	3733
	11th to 20th	Night	43% 5% 9% 16% 19% 8%	3680
	21st to end	Night	40% 4 11% 17% 20% 9%	3466
April	1st to 10th	Night	39% 4 10% 14% 21% 11%	1900
	11th to 20th	Night	38% 4 9% 19% 20% 9%	1875
	21st to end	Night	27% 4 10% 22% 28% 8%	1900
May	1st to 10th	Night	36% 8% 14% 19% 17% 5%	3160
	11th to 20th	Night	39% 7% 14% 21% 17% 1	2958
	21st to end	Night	30% 8% 19% 26% 15% 2	3087
June	1st to 10th	Night	36% 10% 19% 22% 11% 2	1710
	11th to 20th	Night	29% 10% 20% 26% 14% 2	1710
	21st to end	Night	35% 10% 23% 21% 10% 2	1710
July	1st to 10th	Night	39% 14% 28% 14% 5% 1	2814
	11th to 20th	Night	33% 15% 38% 12% 2 1	3100
	21st to end	Night	44% 17% 20% 15% 3	3325
August	1st to 10th	Night	22% 8% 23% 27% 18% 1	3132
	11th to 20th	Night	28% 10% 21% 25% 15% 1	3130
	21st to end	Night	37% 12% 17% 19% 12% 3	3476
September	1st to 10th	Night	41% 10% 16% 14% 13% 6%	1900
	11th to 20th	Night	39% 7% 13% 17% 16% 8%	2042
	21st to end	Night	31% 7% 11% 23% 19% 10%	2090
October	1st to 10th	Night	31% 4 8% 10% 24% 24%	3480
	11th to 20th	Night	16% 2 4 20% 24% 34%	3582
	21st to end	Night	19% 2 5% 12% 39% 23%	4120
November	1st to 10th	Night	31% 3 8% 17% 26% 16%	2491
	11th to 20th	Night	32% 3 6% 16% 28% 15%	2600
	21st to end	Night	35% 4 6% 20% 21% 13%	2600
December	1st to 10th	Night	37% 4 9% 21% 22% 7%	2542
	11th to 20th	Night	42% 3 7% 12% 27% 9%	3044
	21st to end	Night	44% 3 6% 18% 24% 5%	4532

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	26% 18% 36% 15% 5% 1	270
	11th to 20th	Day	24% 12% 35% 21% 7% 1	270
	21st to end	Day	28% 20% 34% 15% 3	297
February	1st to 10th	Day	30% 20% 29% 15% 5% 1	270
	11th to 20th	Day	31% 17% 34% 15% 4	270
	21st to end	Day	25% 22% 37% 13% 3	225
March	1st to 10th	Day	21% 17% 40% 17% 6%	270
	11th to 20th	Day	22% 21% 33% 18% 5%	284
	21st to end	Day	18% 15% 31% 27% 9%	506
April	1st to 10th	Day	21% 13% 31% 23% 10% 2	460
	11th to 20th	Day	19% 12% 30% 25% 12% 3	452
	21st to end	Day	11% 12% 30% 28% 17% 2	460
May	1st to 10th	Day	10% 10% 28% 24% 23% 4	463
	11th to 20th	Day	8% 5% 23% 31% 21% 12%	487
	21st to end	Day	9% 3 17% 33% 23% 14%	529
June	1st to 10th	Day	11% 3 15% 29% 26% 15%	490
	11th to 20th	Day	8% 3 12% 30% 31% 17%	490
	21st to end	Day	11% 2 11% 27% 27% 22%	490
July	1st to 10th	Day	9% 2 6% 23% 34% 26%	485
	11th to 20th	Day	9% 2 3 14% 39% 33%	484
	21st to end	Day	6% 1 5% 22% 40% 26%	532
August	1st to 10th	Day	5% 1 6% 21% 31% 35%	486
	11th to 20th	Day	9% 2 4 18% 36% 31%	479
	21st to end	Day	12% 1 8% 24% 33% 24%	539
September	1st to 10th	Day	10% 2 7% 27% 34% 19%	490
	11th to 20th	Day	14% 4 11% 26% 31% 12%	490
	21st to end	Day	12% 3 12% 32% 28% 14%	490
October	1st to 10th	Day	10% 5% 21% 34% 24% 6%	490
	11th to 20th	Day	11% 6% 18% 33% 25% 6%	414
	21st to end	Day	19% 9% 19% 30% 18% 4	330
November	1st to 10th	Day	16% 9% 25% 36% 13% 2	300
	11th to 20th	Day	18% 14% 30% 26% 10% 1	300
	21st to end	Day	17% 12% 35% 22% 12% 2	300
December	1st to 10th	Day	21% 13% 36% 20% 8% 1	285
	11th to 20th	Day	25% 13% 39% 16% 7%	270
	21st to end	Day	28% 12% 30% 22% 7% 1	297
January	1st to 10th	Night	20% 14% 34% 27% 5%	760
	11th to 20th	Night	20% 14% 27% 31% 8% 1	760
	21st to end	Night	25% 13% 31% 27% 4	836
February	1st to 10th	Night	21% 12% 32% 30% 5%	760
	11th to 20th	Night	25% 14% 31% 22% 6%	743
	21st to end	Night	22% 16% 39% 21% 2	628
March	1st to 10th	Night	18% 14% 33% 28% 7%	760
	11th to 20th	Night	18% 10% 36% 28% 7% 1	708
	21st to end	Night	15% 9% 35% 30% 11%	627
April	1st to 10th	Night	16% 13% 28% 29% 13% 1	570
	11th to 20th	Night	17% 7% 32% 29% 14% 1	563
	21st to end	Night	9% 6% 27% 40% 17% 1	570
May	1st to 10th	Night	12% 4 26% 37% 18% 3	570
	11th to 20th	Night	8% 2 19% 43% 22% 5%	561
	21st to end	Night	8% 1 13% 37% 33% 7%	617
June	1st to 10th	Night	9% 2 9% 35% 37% 8%	570
	11th to 20th	Night	5% 1 9% 33% 38% 14%	570
	21st to end	Night	8% 1 9% 28% 40% 15%	570
July	1st to 10th	Night	7% 1 3 22% 48% 17%	555
	11th to 20th	Night	6% 1 3 18% 45% 27%	552
	21st to end	Night	4 2 3 23% 50% 18%	624
August	1st to 10th	Night	3 1 3 19% 46% 28%	567
	11th to 20th	Night	8% 1 4 20% 46% 21%	564
	21st to end	Night	10% 2 5% 22% 44% 17%	627
September	1st to 10th	Night	10% 2 6% 26% 41% 14%	570
	11th to 20th	Night	11% 4 9% 28% 39% 8%	712
	21st to end	Night	11% 2 10% 31% 41% 5%	760
October	1st to 10th	Night	10% 2 22% 33% 28% 5%	760
	11th to 20th	Night	12% 4 23% 31% 28% 4	760
	21st to end	Night	15% 5% 21% 34% 24% 2	836
November	1st to 10th	Night	11% 7% 21% 41% 19% 2	780
	11th to 20th	Night	16% 8% 26% 33% 15% 1	800
	21st to end	Night	15% 11% 25% 33% 15% 1	800
December	1st to 10th	Night	17% 11% 29% 29% 13% 1	783
	11th to 20th	Night	23% 6% 31% 30% 9%	760
	21st to end	Night	24% 11% 30% 28% 7%	836

Page generated at 2024-12-03 05:45:09. Version ac07

Copyright © 2024 Attilla Danko.