Hemlock Crossings Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hemlock Crossings Park clear sky chart from 2005-11-06 to 2024-11-02.

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	13% 10% 4 8% 5% 4 4 3 5% 7% 36%	101246
	Night	15% 13% 5% 9% 5% 4 4 3 4 6% 31%	97780
Transparency	Day	47% 6% 12% 21% 12% 1	101037
	Night	54% 6% 10% 17% 11% 1	97661
Seeing	Day	16% 8% 24% 29% 17% 5%	15828
	Night	20% 8% 26% 30% 15% 2	25671

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	14% 25% 10% 16% 8% 5% 4 2 3 3 9%	2527
	11th to 20th	Day	12% 18% 8% 19% 16% 9% 4 3 3 3 6%	2530
	21st to end	Day	20% 23% 9% 19% 7% 4 4 2 2 2 8%	2783
February	1st to 10th	Day	12% 16% 6% 16% 12% 5% 5% 3 4 4 17%	1739
	11th to 20th	Day	13% 14% 6% 14% 10% 6% 4 3 5% 5% 21%	1848
	21st to end	Day	15% 15% 5% 11% 7% 6% 4 4 5% 6% 21%	1570
March	1st to 10th	Day	14% 12% 4 8% 5% 5% 5% 4 5% 6% 31%	3120
	11th to 20th	Day	11% 8% 6% 11% 6% 5% 4 4 5% 7% 34%	3346
	21st to end	Day	20% 12% 7% 9% 5% 3 3 3 4 6% 28%	4019
April	1st to 10th	Day	19% 12% 3 7% 4 4 4 4 5% 6% 32%	2280
	11th to 20th	Day	17% 10% 3 6% 4 4 4 4 5% 7% 38%	2286
	21st to end	Day	16% 9% 3 7% 5% 4 4 4 5% 7% 36%	2470
May	1st to 10th	Day	16% 6% 2 6% 4 4 5% 3 6% 8% 40%	4082
	11th to 20th	Day	13% 7% 2 6% 4 4 4 3 5% 9% 44%	4141
	21st to end	Day	9% 6% 2 5% 4 4 4 4 6% 9% 47%	4824
June	1st to 10th	Day	10% 5% 2 5% 4 5% 4 3 6% 8% 47%	2660
	11th to 20th	Day	10% 5% 2 5% 4 4 4 3 5% 9% 51%	2660
	21st to end	Day	10% 6% 2 6% 3 4 4 4 6% 8% 46%	2660
July	1st to 10th	Day	12% 7% 3 7% 4 4 5% 4 6% 8% 41%	4440
	11th to 20th	Day	6% 4 2 4 3 4 5% 4 6% 9% 54%	4440
	21st to end	Day	7% 5% 2 5% 4 4 5% 4 6% 9% 49%	4813
August	1st to 10th	Day	11% 5% 2 5% 3 4 4 4 6% 10% 45%	4199
	11th to 20th	Day	11% 5% 2 5% 3 3 4 4 6% 7% 51%	4029
	21st to end	Day	8% 5% 2 6% 4 4 4 3 6% 8% 49%	4180
September	1st to 10th	Day	10% 6% 2 5% 5% 4 3 3 5% 8% 47%	2271
	11th to 20th	Day	11% 5% 2 5% 3 4 4 4 6% 8% 49%	2090
	21st to end	Day	12% 7% 3 7% 5% 5% 4 3 5% 8% 42%	2090
October	1st to 10th	Day	16% 7% 2 6% 5% 4 4 2 4 6% 44%	2090
	11th to 20th	Day	22% 11% 3 7% 5% 5% 5% 4 6% 6% 25%	1841
	21st to end	Day	23% 12% 3 9% 6% 5% 4 3 5% 6% 23%	1881
November	1st to 10th	Day	14% 13% 3 8% 5% 4 4 3 5% 6% 34%	1681
	11th to 20th	Day	17% 21% 6% 12% 5% 5% 4 3 5% 4 21%	1710
	21st to end	Day	22% 20% 6% 9% 5% 3 4 3 3 5% 21%	1710
December	1st to 10th	Day	14% 27% 10% 14% 6% 4 3 2 3 5% 12%	1535
	11th to 20th	Day	15% 22% 11% 15% 6% 5% 4 3 4 3 11%	1918
	21st to end	Day	20% 26% 8% 14% 6% 3 3 2 4 4 9%	2783
January	1st to 10th	Night	15% 24% 11% 16% 7% 4 3 2 3 3 11%	4428
	11th to 20th	Night	14% 20% 11% 19% 11% 7% 3 2 3 2 8%	4440
	21st to end	Night	22% 21% 9% 15% 7% 5% 4 2 3 3 9%	4884
February	1st to 10th	Night	12% 20% 5% 16% 9% 5% 3 3 3 4 18%	2434
	11th to 20th	Night	13% 17% 7% 14% 7% 5% 4 3 3 4 22%	2218
	21st to end	Night	17% 16% 4 12% 6% 5% 4 4 4 5% 23%	1884
March	1st to 10th	Night	16% 9% 4 8% 5% 5% 4 3 5% 6% 35%	3733
	11th to 20th	Night	10% 8% 3 8% 5% 5% 4 3 5% 7% 43%	3613
	21st to end	Night	17% 12% 5% 11% 6% 5% 4 3 4 5% 27%	3640
April	1st to 10th	Night	15% 10% 3 7% 5% 4 5% 4 5% 6% 35%	1900
	11th to 20th	Night	20% 9% 2 6% 4 4 4 4 5% 6% 35%	1843
	21st to end	Night	17% 7% 3 6% 4 4 5% 4 6% 7% 37%	1710
May	1st to 10th	Night	14% 9% 3 8% 6% 4 5% 4 5% 6% 35%	2813
	11th to 20th	Night	18% 7% 3 6% 3 3 4 4 5% 8% 39%	2751
	21st to end	Night	15% 7% 3 7% 5% 4 4 3 5% 7% 41%	2743
June	1st to 10th	Night	10% 6% 2 5% 5% 4 5% 5% 6% 8% 44%	1520
	11th to 20th	Night	9% 7% 2 7% 4 4 4 4 5% 9% 44%	1520
	21st to end	Night	9% 6% 2 6% 5% 4 5% 4 7% 9% 43%	1520
July	1st to 10th	Night	9% 6% 2 7% 5% 5% 5% 4 6% 8% 41%	2530
	11th to 20th	Night	6% 4 1 4 4 4 3 4 5% 7% 56%	2530
	21st to end	Night	7% 5% 2 7% 4 4 4 4 6% 8% 49%	2750
August	1st to 10th	Night	9% 5% 3 6% 4 3 4 3 6% 9% 49%	2732
	11th to 20th	Night	11% 4 2 5% 4 3 4 4 5% 8% 50%	2785
	21st to end	Night	8% 6% 2 7% 4 4 4 4 5% 8% 46%	3474
September	1st to 10th	Night	10% 5% 2 6% 4 4 4 3 5% 6% 50%	1900
	11th to 20th	Night	11% 4 2 5% 3 3 3 3 5% 6% 54%	2080
	21st to end	Night	12% 8% 2 7% 5% 5% 4 3 5% 7% 43%	2090
October	1st to 10th	Night	18% 6% 2 5% 4 3 3 3 4 7% 45%	2090
	11th to 20th	Night	23% 12% 3 7% 4 4 3 2 4 6% 34%	2333
	21st to end	Night	26% 11% 3 7% 3 3 4 3 4 5% 31%	2717
November	1st to 10th	Night	16% 14% 3 6% 5% 4 4 2 4 6% 35%	2431
	11th to 20th	Night	19% 19% 6% 10% 5% 4 3 3 5% 5% 20%	2470
	21st to end	Night	19% 21% 6% 11% 4 3 4 2 3 6% 21%	2470
December	1st to 10th	Night	17% 28% 7% 12% 5% 4 3 3 4 4 13%	2641
	11th to 20th	Night	16% 23% 8% 15% 5% 4 4 2 4 4 14%	3279
	21st to end	Night	26% 23% 7% 11% 4 4 3 3 4 4 11%	4884

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	79% 8% 6% 6% 1	2528
	11th to 20th	Day	84% 6% 6% 3 1	2530
	21st to end	Day	83% 6% 6% 4 2	2783
February	1st to 10th	Day	71% 7% 7% 13% 3	1739
	11th to 20th	Day	66% 5% 10% 13% 6% 1	1858
	21st to end	Day	62% 7% 13% 13% 5%	1570
March	1st to 10th	Day	51% 6% 14% 20% 8%	3120
	11th to 20th	Day	48% 6% 16% 19% 10% 1	3346
	21st to end	Day	57% 5% 12% 19% 7% 1	4019
April	1st to 10th	Day	52% 6% 11% 20% 11%	2280
	11th to 20th	Day	45% 6% 11% 21% 15% 3	2286
	21st to end	Day	46% 6% 13% 19% 14% 2	2470
May	1st to 10th	Day	40% 8% 12% 24% 14% 1	4120
	11th to 20th	Day	37% 9% 15% 22% 14% 3	4145
	21st to end	Day	32% 8% 13% 23% 21% 2	4837
June	1st to 10th	Day	34% 7% 13% 28% 17% 2	2660
	11th to 20th	Day	31% 8% 14% 24% 21% 1	2660
	21st to end	Day	34% 7% 15% 24% 18% 2	2660
July	1st to 10th	Day	41% 6% 13% 24% 14% 3	4371
	11th to 20th	Day	25% 6% 15% 33% 19% 2	4365
	21st to end	Day	31% 6% 17% 22% 21% 2	4662
August	1st to 10th	Day	35% 6% 13% 31% 14% 1	4184
	11th to 20th	Day	31% 7% 13% 31% 16% 1	4068
	21st to end	Day	33% 5% 15% 27% 18% 2	4179
September	1st to 10th	Day	34% 7% 15% 27% 14% 2	2271
	11th to 20th	Day	32% 7% 13% 30% 16% 2	2090
	21st to end	Day	41% 6% 12% 24% 16%	2090
October	1st to 10th	Day	43% 6% 9% 28% 14% 1	2090
	11th to 20th	Day	57% 7% 12% 15% 8%	1841
	21st to end	Day	61% 6% 12% 15% 6%	1881
November	1st to 10th	Day	51% 7% 11% 19% 11% 1	1681
	11th to 20th	Day	67% 6% 9% 13% 4 1	1710
	21st to end	Day	67% 5% 12% 11% 4	1710
December	1st to 10th	Day	78% 5% 7% 7% 2	1535
	11th to 20th	Day	76% 8% 9% 6% 1	1915
	21st to end	Day	80% 5% 6% 7% 1	2783
January	1st to 10th	Night	77% 6% 8% 6% 2	4428
	11th to 20th	Night	84% 5% 5% 4 2	4440
	21st to end	Night	81% 7% 7% 3 1	4884
February	1st to 10th	Night	71% 5% 9% 10% 5%	2434
	11th to 20th	Night	66% 6% 7% 15% 6%	2219
	21st to end	Night	63% 6% 11% 13% 6% 1	1884
March	1st to 10th	Night	49% 7% 12% 24% 7%	3733
	11th to 20th	Night	38% 8% 13% 24% 13% 3	3613
	21st to end	Night	58% 6% 9% 18% 8% 1	3640
April	1st to 10th	Night	48% 7% 11% 19% 14% 1	1900
	11th to 20th	Night	49% 5% 8% 17% 18% 3	1843
	21st to end	Night	44% 7% 11% 19% 15% 4	1710
May	1st to 10th	Night	47% 7% 11% 19% 14% 2	2840
	11th to 20th	Night	43% 7% 10% 22% 15% 4	2752
	21st to end	Night	43% 7% 8% 18% 20% 3	2751
June	1st to 10th	Night	35% 7% 10% 27% 18% 3	1520
	11th to 20th	Night	36% 6% 11% 25% 20% 2	1520
	21st to end	Night	35% 8% 14% 24% 16% 3	1520
July	1st to 10th	Night	40% 6% 11% 24% 12% 7%	2490
	11th to 20th	Night	27% 6% 13% 27% 25% 2	2482
	21st to end	Night	34% 6% 12% 20% 26% 3	2662
August	1st to 10th	Night	33% 6% 13% 29% 19% 1	2723
	11th to 20th	Night	32% 7% 9% 32% 18% 1	2812
	21st to end	Night	36% 6% 10% 25% 21% 2	3474
September	1st to 10th	Night	34% 6% 13% 26% 18% 3	1900
	11th to 20th	Night	30% 6% 11% 32% 20% 2	2080
	21st to end	Night	42% 7% 11% 25% 13% 1	2090
October	1st to 10th	Night	40% 5% 8% 29% 17% 1	2090
	11th to 20th	Night	53% 5% 12% 20% 10% 1	2333
	21st to end	Night	56% 6% 12% 17% 9%	2717
November	1st to 10th	Night	51% 7% 9% 20% 11% 1	2431
	11th to 20th	Night	65% 6% 10% 13% 5% 1	2470
	21st to end	Night	66% 6% 13% 14% 2	2470
December	1st to 10th	Night	76% 6% 7% 8% 3	2641
	11th to 20th	Night	73% 8% 10% 6% 2	3281
	21st to end	Night	77% 6% 10% 6% 2	4884

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	22% 11% 33% 26% 5% 3	270
	11th to 20th	Day	22% 15% 30% 24% 7% 1	270
	21st to end	Day	27% 8% 31% 28% 6% 1	297
February	1st to 10th	Day	17% 16% 37% 21% 7% 2	270
	11th to 20th	Day	19% 16% 36% 22% 7% 1	270
	21st to end	Day	21% 12% 40% 20% 5%	225
March	1st to 10th	Day	19% 13% 39% 22% 7%	270
	11th to 20th	Day	17% 12% 30% 28% 12% 1	378
	21st to end	Day	26% 10% 26% 28% 8% 2	506
April	1st to 10th	Day	23% 8% 31% 29% 9%	460
	11th to 20th	Day	20% 14% 29% 25% 9% 4	452
	21st to end	Day	22% 8% 28% 27% 13% 2	460
May	1st to 10th	Day	21% 8% 28% 30% 12% 2	463
	11th to 20th	Day	17% 6% 21% 33% 19% 4	521
	21st to end	Day	14% 4 22% 31% 23% 7%	734
June	1st to 10th	Day	11% 4 24% 36% 21% 4	680
	11th to 20th	Day	12% 5% 21% 37% 20% 5%	680
	21st to end	Day	12% 6% 23% 38% 17% 4	680
July	1st to 10th	Day	7% 3 20% 33% 27% 11%	671
	11th to 20th	Day	8% 3 21% 36% 24% 8%	668
	21st to end	Day	9% 1 18% 42% 23% 7%	739
August	1st to 10th	Day	11% 4 14% 30% 30% 12%	543
	11th to 20th	Day	11% 5% 14% 30% 29% 12%	479
	21st to end	Day	10% 4 15% 31% 29% 11%	539
September	1st to 10th	Day	14% 5% 15% 32% 25% 9%	490
	11th to 20th	Day	8% 4 14% 28% 29% 17%	490
	21st to end	Day	15% 7% 22% 22% 23% 10%	490
October	1st to 10th	Day	18% 7% 25% 25% 18% 7%	490
	11th to 20th	Day	25% 16% 24% 28% 7% 1	363
	21st to end	Day	31% 11% 31% 20% 5% 2	330
November	1st to 10th	Day	21% 16% 26% 25% 10% 3	273
	11th to 20th	Day	24% 20% 31% 19% 4	270
	21st to end	Day	27% 12% 38% 17% 5%	270
December	1st to 10th	Day	24% 21% 29% 18% 7% 1	270
	11th to 20th	Day	21% 20% 31% 22% 5% 1	270
	21st to end	Day	27% 18% 34% 16% 3 1	297
January	1st to 10th	Night	23% 15% 31% 23% 7%	950
	11th to 20th	Night	25% 13% 32% 24% 6% 1	950
	21st to end	Night	23% 10% 33% 28% 6%	1045
February	1st to 10th	Night	21% 11% 35% 27% 6% 1	819
	11th to 20th	Night	22% 10% 34% 27% 7%	743
	21st to end	Night	25% 12% 36% 24% 4	628
March	1st to 10th	Night	20% 8% 31% 32% 8% 1	760
	11th to 20th	Night	15% 9% 32% 33% 10% 1	760
	21st to end	Night	21% 7% 28% 30% 12% 1	736
April	1st to 10th	Night	17% 8% 32% 33% 9% 1	570
	11th to 20th	Night	25% 9% 24% 32% 10% 1	563
	21st to end	Night	19% 5% 28% 35% 11% 2	570
May	1st to 10th	Night	18% 5% 24% 38% 14% 2	570
	11th to 20th	Night	20% 2 22% 32% 22% 1	561
	21st to end	Night	15% 3 17% 35% 25% 4	617
June	1st to 10th	Night	12% 2 20% 40% 23% 2	570
	11th to 20th	Night	11% 4 22% 37% 24% 2	570
	21st to end	Night	11% 4 17% 39% 28% 2	570
July	1st to 10th	Night	9% 2 13% 35% 36% 6%	555
	11th to 20th	Night	7% 2 14% 39% 32% 5%	552
	21st to end	Night	9% 1 13% 39% 34% 3	624
August	1st to 10th	Night	8% 2 12% 40% 32% 6%	567
	11th to 20th	Night	11% 3 11% 37% 31% 7%	564
	21st to end	Night	11% 2 14% 37% 32% 4	627
September	1st to 10th	Night	12% 3 15% 37% 28% 5%	570
	11th to 20th	Night	12% 3 13% 34% 31% 7%	750
	21st to end	Night	15% 6% 23% 26% 24% 6%	760
October	1st to 10th	Night	22% 4 21% 31% 20% 3	760
	11th to 20th	Night	29% 10% 23% 25% 11% 1	760
	21st to end	Night	31% 10% 30% 22% 7% 1	836
November	1st to 10th	Night	24% 9% 28% 26% 11% 1	748
	11th to 20th	Night	28% 15% 31% 21% 5%	760
	21st to end	Night	28% 13% 29% 24% 5%	760
December	1st to 10th	Night	28% 15% 32% 19% 5%	931
	11th to 20th	Night	27% 14% 34% 20% 5%	950
	21st to end	Night	32% 11% 35% 19% 2	1045

Page generated at 2024-10-30 13:19:21. Version ac07

Copyright © 2024 Attilla Danko.