Litchfield High School
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Litchfield High School clear sky chart from 2005-11-06 to 2024-11-28.

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	12% 8% 3 8% 5% 4 5% 4 6% 7% 38%	102156
	Night	12% 9% 3 8% 5% 4 4 3 5% 7% 40%	97445
Transparency	Day	43% 6% 13% 25% 11% 1	105782
	Night	42% 5% 13% 25% 13% 2	101960
Seeing	Day	16% 9% 31% 28% 14% 3	16101
	Night	15% 9% 33% 32% 11% 1	26013

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	10% 17% 4 17% 8% 5% 5% 3 5% 6% 20%	2291
	11th to 20th	Day	6% 9% 4 14% 9% 7% 9% 5% 8% 6% 21%	2659
	21st to end	Day	6% 17% 9% 13% 8% 7% 6% 4 5% 7% 20%	3135
February	1st to 10th	Day	8% 12% 4 10% 6% 6% 5% 5% 6% 7% 31%	1710
	11th to 20th	Day	8% 10% 4 9% 7% 5% 5% 5% 6% 7% 33%	1664
	21st to end	Day	10% 12% 3 9% 7% 5% 5% 4 6% 7% 32%	1432
March	1st to 10th	Day	11% 12% 4 9% 5% 5% 4 3 6% 6% 35%	3436
	11th to 20th	Day	10% 8% 3 8% 5% 4 5% 3 5% 7% 42%	3480
	21st to end	Day	23% 11% 4 11% 8% 5% 5% 3 4 5% 21%	3814
April	1st to 10th	Day	17% 10% 3 7% 4 3 4 4 6% 6% 36%	2251
	11th to 20th	Day	18% 11% 4 8% 5% 4 4 4 4 6% 32%	2342
	21st to end	Day	23% 11% 2 7% 4 4 4 4 5% 6% 32%	2470
May	1st to 10th	Day	17% 6% 2 6% 4 5% 5% 4 6% 7% 39%	4146
	11th to 20th	Day	13% 6% 2 6% 5% 4 4 3 5% 7% 45%	4399
	21st to end	Day	18% 6% 2 6% 5% 4 5% 4 7% 8% 36%	4824
June	1st to 10th	Day	11% 5% 2 5% 4 4 4 5% 7% 7% 45%	2669
	11th to 20th	Day	13% 7% 2 6% 5% 4 5% 5% 6% 8% 38%	2850
	21st to end	Day	9% 5% 2 5% 4 5% 5% 4 7% 9% 44%	2850
July	1st to 10th	Day	9% 5% 2 6% 5% 5% 6% 6% 8% 11% 38%	4750
	11th to 20th	Day	5% 3 1 3 3 3 3 3 5% 9% 60%	4533
	21st to end	Day	5% 4 2 6% 5% 5% 5% 4 7% 9% 49%	4629
August	1st to 10th	Day	12% 6% 2 6% 4 4 4 4 6% 8% 44%	4104
	11th to 20th	Day	12% 6% 2 6% 5% 5% 5% 4 7% 9% 40%	4041
	21st to end	Day	9% 6% 2 6% 4 4 4 3 5% 8% 49%	4420
September	1st to 10th	Day	10% 4 2 5% 4 4 4 4 5% 8% 51%	2280
	11th to 20th	Day	12% 4 2 6% 4 4 5% 3 6% 8% 46%	2174
	21st to end	Day	15% 6% 2 5% 3 3 3 3 4 8% 47%	2047
October	1st to 10th	Day	17% 7% 2 6% 4 4 3 3 5% 6% 43%	1900
	11th to 20th	Day	15% 9% 3 6% 4 3 4 3 4 8% 41%	1900
	21st to end	Day	17% 10% 4 6% 4 3 3 3 5% 7% 38%	2090
November	1st to 10th	Day	13% 10% 4 8% 5% 4 3 4 5% 6% 37%	1607
	11th to 20th	Day	9% 13% 5% 13% 6% 4 5% 4 5% 5% 31%	1600
	21st to end	Day	13% 10% 4 8% 6% 5% 5% 3 7% 8% 32%	1576
December	1st to 10th	Day	9% 12% 5% 11% 7% 7% 6% 4 6% 6% 26%	1520
	11th to 20th	Day	10% 14% 7% 11% 6% 5% 4 3 5% 6% 30%	1918
	21st to end	Day	22% 14% 4 17% 4 3 3 3 4 6% 20%	2645
January	1st to 10th	Night	10% 13% 6% 17% 7% 4 4 3 5% 6% 27%	4642
	11th to 20th	Night	6% 11% 5% 13% 9% 8% 9% 6% 7% 6% 21%	4308
	21st to end	Night	8% 18% 9% 12% 6% 4 4 4 5% 5% 26%	4532
February	1st to 10th	Night	6% 11% 5% 8% 7% 5% 5% 4 5% 6% 36%	2470
	11th to 20th	Night	6% 9% 3 7% 5% 5% 5% 4 6% 8% 40%	2403
	21st to end	Night	11% 10% 3 7% 5% 5% 5% 4 6% 6% 37%	2037
March	1st to 10th	Night	8% 8% 3 7% 4 4 4 3 5% 7% 47%	3419
	11th to 20th	Night	8% 7% 3 8% 5% 4 5% 4 6% 8% 42%	3480
	21st to end	Night	25% 12% 4 9% 5% 3 3 2 4 5% 28%	3817
April	1st to 10th	Night	14% 9% 3 7% 4 4 3 4 5% 6% 39%	1928
	11th to 20th	Night	19% 11% 3 7% 4 3 3 4 5% 5% 37%	1784
	21st to end	Night	19% 10% 2 7% 5% 4 3 3 5% 6% 37%	1710
May	1st to 10th	Night	15% 7% 2 6% 4 4 4 4 4 5% 45%	2759
	11th to 20th	Night	14% 5% 2 5% 3 3 4 3 6% 8% 47%	2506
	21st to end	Night	17% 7% 2 6% 3 3 3 3 5% 8% 43%	2743
June	1st to 10th	Night	11% 3 2 5% 4 4 4 4 6% 8% 50%	1506
	11th to 20th	Night	8% 6% 2 5% 4 4 4 4 7% 8% 48%	1330
	21st to end	Night	9% 3 1 4 3 4 4 4 5% 7% 56%	1330
July	1st to 10th	Night	11% 4 2 5% 3 5% 5% 4 7% 9% 45%	2220
	11th to 20th	Night	3 3 1 4 3 3 3 3 5% 8% 63%	2432
	21st to end	Night	5% 4 1 4 4 3 3 4 6% 8% 57%	2929
August	1st to 10th	Night	11% 6% 2 6% 4 3 4 3 5% 7% 50%	2836
	11th to 20th	Night	12% 4 2 5% 4 3 5% 3 6% 8% 49%	2798
	21st to end	Night	8% 5% 2 6% 4 3 4 3 5% 8% 52%	3242
September	1st to 10th	Night	8% 3 2 5% 3 3 4 3 6% 8% 57%	1900
	11th to 20th	Night	10% 4 2 5% 3 3 4 3 5% 7% 55%	2004
	21st to end	Night	10% 6% 2 5% 3 3 3 3 4 6% 55%	2114
October	1st to 10th	Night	15% 5% 2 5% 4 3 4 3 4 7% 49%	2280
	11th to 20th	Night	14% 9% 3 5% 4 3 4 3 5% 6% 44%	2280
	21st to end	Night	17% 11% 3 7% 3 3 3 3 5% 6% 39%	2508
November	1st to 10th	Night	11% 8% 3 6% 4 4 4 4 6% 6% 43%	2688
	11th to 20th	Night	12% 11% 5% 10% 5% 4 4 3 4 5% 36%	2800
	21st to end	Night	12% 10% 4 8% 5% 4 4 3 6% 6% 39%	2759
December	1st to 10th	Night	9% 11% 5% 11% 7% 5% 4 4 5% 7% 32%	2660
	11th to 20th	Night	11% 11% 4 11% 7% 6% 6% 5% 5% 6% 28%	3279
	21st to end	Night	21% 14% 5% 13% 6% 4 4 3 4 5% 22%	5012

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	65% 5% 10% 15% 4	2292
	11th to 20th	Day	59% 6% 12% 18% 5%	2659
	21st to end	Day	63% 7% 12% 14% 4	3135
February	1st to 10th	Day	50% 6% 13% 22% 8% 1	1710
	11th to 20th	Day	51% 5% 14% 21% 8% 1	1673
	21st to end	Day	51% 7% 10% 21% 11%	1432
March	1st to 10th	Day	48% 6% 12% 24% 9% 1	3436
	11th to 20th	Day	41% 5% 11% 30% 11% 2	3480
	21st to end	Day	65% 5% 9% 17% 4	3814
April	1st to 10th	Day	48% 6% 11% 23% 12% 2	2251
	11th to 20th	Day	52% 6% 11% 18% 12% 1	2342
	21st to end	Day	53% 6% 11% 20% 9% 1	2470
May	1st to 10th	Day	42% 8% 11% 24% 15% 1	4184
	11th to 20th	Day	38% 6% 10% 30% 14% 2	4403
	21st to end	Day	44% 8% 13% 27% 9% 1	4837
June	1st to 10th	Day	33% 8% 16% 29% 12% 1	2669
	11th to 20th	Day	42% 8% 13% 21% 14% 1	2850
	21st to end	Day	33% 8% 18% 28% 11% 2	2850
July	1st to 10th	Day	37% 6% 21% 23% 12%	4676
	11th to 20th	Day	21% 5% 18% 37% 17% 2	4455
	21st to end	Day	30% 7% 16% 32% 15% 1	4483
August	1st to 10th	Day	38% 6% 12% 30% 12% 2	4090
	11th to 20th	Day	40% 6% 14% 32% 8%	4080
	21st to end	Day	34% 5% 19% 29% 13% 1	4419
September	1st to 10th	Day	32% 6% 13% 36% 13%	2280
	11th to 20th	Day	35% 7% 17% 31% 10%	2174
	21st to end	Day	37% 5% 11% 34% 12% 1	2047
October	1st to 10th	Day	32% 3 8% 33% 23%	3160
	11th to 20th	Day	37% 4 13% 23% 22% 2	3140
	21st to end	Day	45% 3 16% 27% 10%	3428
November	1st to 10th	Day	46% 6% 12% 21% 12% 3	1607
	11th to 20th	Day	54% 5% 12% 18% 10% 1	1600
	21st to end	Day	49% 5% 16% 22% 7% 2	1576
December	1st to 10th	Day	55% 8% 14% 16% 7%	1520
	11th to 20th	Day	56% 5% 16% 18% 5%	1915
	21st to end	Day	67% 4 10% 14% 5%	2645
January	1st to 10th	Night	59% 5% 11% 19% 6%	4642
	11th to 20th	Night	60% 7% 11% 17% 5%	4308
	21st to end	Night	61% 4 10% 19% 6% 1	4532
February	1st to 10th	Night	48% 4 14% 21% 12% 1	2470
	11th to 20th	Night	41% 6% 16% 24% 11% 2	2404
	21st to end	Night	46% 6% 12% 21% 13% 2	2037
March	1st to 10th	Night	35% 5% 14% 28% 16% 2	3419
	11th to 20th	Night	38% 6% 11% 30% 15% 1	3480
	21st to end	Night	60% 3 9% 20% 6% 1	3817
April	1st to 10th	Night	45% 5% 12% 26% 12% 1	1928
	11th to 20th	Night	48% 4 7% 22% 16% 2	1784
	21st to end	Night	48% 6% 9% 21% 14% 2	1710
May	1st to 10th	Night	40% 6% 11% 24% 16% 3	2786
	11th to 20th	Night	34% 7% 11% 24% 20% 4	2507
	21st to end	Night	39% 6% 13% 27% 14% 1	2751
June	1st to 10th	Night	30% 6% 15% 31% 15% 3	1506
	11th to 20th	Night	32% 6% 16% 26% 17% 3	1330
	21st to end	Night	25% 7% 15% 31% 18% 3	1330
July	1st to 10th	Night	35% 6% 21% 23% 14% 1	2185
	11th to 20th	Night	19% 4 15% 40% 20% 3	2388
	21st to end	Night	25% 6% 16% 35% 16% 3	2836
August	1st to 10th	Night	35% 5% 13% 28% 15% 5%	2826
	11th to 20th	Night	34% 5% 16% 33% 12%	2825
	21st to end	Night	31% 5% 18% 30% 14% 2	3242
September	1st to 10th	Night	25% 6% 15% 34% 18% 1	1900
	11th to 20th	Night	29% 6% 15% 32% 18%	2004
	21st to end	Night	31% 4 12% 34% 17% 1	2114
October	1st to 10th	Night	23% 3 5% 37% 27% 4	3800
	11th to 20th	Night	32% 3 11% 29% 22% 3	3779
	21st to end	Night	42% 3 12% 30% 13% 1	4120
November	1st to 10th	Night	40% 5% 15% 24% 13% 2	2688
	11th to 20th	Night	50% 5% 12% 19% 13% 1	2800
	21st to end	Night	46% 5% 17% 23% 7% 1	2759
December	1st to 10th	Night	52% 6% 15% 20% 7%	2660
	11th to 20th	Night	54% 8% 13% 18% 6% 1	3281
	21st to end	Night	65% 6% 9% 16% 5%	5012

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	15% 9% 31% 26% 16% 2	270
	11th to 20th	Day	16% 11% 36% 33% 4 1	270
	21st to end	Day	15% 8% 41% 23% 11% 2	297
February	1st to 10th	Day	13% 11% 42% 29% 3	270
	11th to 20th	Day	16% 17% 33% 27% 7% 1	270
	21st to end	Day	16% 10% 41% 27% 5%	225
March	1st to 10th	Day	20% 11% 42% 21% 5% 1	270
	11th to 20th	Day	16% 10% 39% 24% 9% 1	270
	21st to end	Day	25% 13% 24% 25% 10% 2	297
April	1st to 10th	Day	24% 14% 32% 24% 6%	431
	11th to 20th	Day	26% 14% 25% 23% 10% 1	540
	21st to end	Day	26% 9% 33% 20% 10% 2	650
May	1st to 10th	Day	20% 10% 37% 23% 9% 1	653
	11th to 20th	Day	18% 9% 29% 26% 14% 3	675
	21st to end	Day	17% 7% 31% 28% 13% 3	734
June	1st to 10th	Day	10% 8% 27% 31% 20% 5%	680
	11th to 20th	Day	17% 7% 33% 31% 11% 2	680
	21st to end	Day	13% 6% 32% 30% 16% 4	680
July	1st to 10th	Day	8% 3 24% 34% 24% 8%	671
	11th to 20th	Day	9% 6% 26% 31% 22% 7%	668
	21st to end	Day	6% 3 24% 38% 24% 5%	739
August	1st to 10th	Day	13% 3 20% 34% 25% 4	676
	11th to 20th	Day	13% 5% 20% 35% 22% 5%	665
	21st to end	Day	10% 5% 26% 33% 22% 4	688
September	1st to 10th	Day	12% 8% 28% 33% 16% 4	490
	11th to 20th	Day	13% 5% 29% 30% 18% 5%	384
	21st to end	Day	20% 11% 29% 21% 15% 5%	300
October	1st to 10th	Day	17% 11% 30% 24% 13% 5%	300
	11th to 20th	Day	14% 18% 39% 20% 9% 1	300
	21st to end	Day	25% 11% 39% 16% 8%	330
November	1st to 10th	Day	20% 12% 33% 24% 8% 2	300
	11th to 20th	Day	16% 15% 44% 21% 4	300
	21st to end	Day	20% 14% 37% 22% 5%	291
December	1st to 10th	Day	12% 11% 40% 27% 9% 1	270
	11th to 20th	Day	17% 12% 37% 29% 5%	270
	21st to end	Day	29% 9% 35% 23% 3	297
January	1st to 10th	Night	11% 11% 38% 30% 9% 1	950
	11th to 20th	Night	14% 11% 36% 32% 7% 1	950
	21st to end	Night	17% 11% 36% 29% 8%	1045
February	1st to 10th	Night	12% 11% 38% 31% 8% 1	950
	11th to 20th	Night	11% 12% 41% 29% 6% 1	929
	21st to end	Night	15% 10% 35% 29% 9% 1	781
March	1st to 10th	Night	16% 9% 40% 25% 10% 1	570
	11th to 20th	Night	17% 10% 38% 29% 6% 1	570
	21st to end	Night	22% 9% 30% 27% 10% 2	627
April	1st to 10th	Night	19% 9% 38% 27% 6%	570
	11th to 20th	Night	22% 13% 29% 27% 9% 1	563
	21st to end	Night	24% 8% 32% 27% 9% 1	570
May	1st to 10th	Night	19% 8% 34% 30% 8% 1	570
	11th to 20th	Night	16% 8% 34% 30% 10% 1	561
	21st to end	Night	17% 7% 27% 36% 12% 1	617
June	1st to 10th	Night	12% 5% 29% 38% 15% 1	570
	11th to 20th	Night	9% 4 36% 40% 10%	570
	21st to end	Night	9% 4 25% 45% 16% 1	570
July	1st to 10th	Night	6% 2 24% 40% 26% 2	555
	11th to 20th	Night	5% 3 25% 48% 18% 1	552
	21st to end	Night	6% 1 22% 47% 21% 2	624
August	1st to 10th	Night	10% 3 17% 47% 21% 2	567
	11th to 20th	Night	11% 4 17% 42% 24% 3	564
	21st to end	Night	8% 4 26% 38% 22% 2	627
September	1st to 10th	Night	8% 5% 26% 40% 19% 2	570
	11th to 20th	Night	11% 6% 30% 33% 18% 2	570
	21st to end	Night	11% 10% 33% 31% 14% 2	594
October	1st to 10th	Night	18% 6% 33% 29% 12% 1	760
	11th to 20th	Night	19% 10% 36% 27% 8% 1	760
	21st to end	Night	23% 11% 32% 27% 7%	836
November	1st to 10th	Night	16% 10% 34% 31% 9%	970
	11th to 20th	Night	17% 13% 37% 26% 6% 1	1000
	21st to end	Night	17% 13% 35% 27% 7%	986
December	1st to 10th	Night	14% 11% 37% 29% 8% 1	950
	11th to 20th	Night	20% 8% 38% 26% 7% 1	950
	21st to end	Night	24% 10% 32% 27% 5% 1	1045

Page generated at 2024-11-24 23:22:21. Version ac07

Copyright © 2024 Attilla Danko.