Warman Observatory
Clear Sky Chart
History

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

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% 9% 3 8% 5% 5% 5% 4 6% 7% 37%	102362
	Night	12% 9% 3 8% 5% 4 4 4 5% 7% 38%	96897
Transparency	Day	44% 7% 14% 25% 10% 1	105949
	Night	44% 6% 13% 24% 12% 1	101451
Seeing	Day	16% 9% 30% 27% 13% 4	16097
	Night	16% 8% 31% 32% 11% 1	25979

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	11% 15% 4 14% 7% 6% 4 4 5% 6% 24%	2527
	11th to 20th	Day	5% 10% 4 15% 9% 10% 9% 6% 8% 6% 19%	2530
	21st to end	Day	6% 18% 9% 13% 6% 6% 5% 4 5% 7% 21%	3081
February	1st to 10th	Day	9% 12% 4 10% 6% 6% 4 3 5% 7% 34%	1710
	11th to 20th	Day	7% 11% 4 9% 7% 5% 5% 3 5% 7% 37%	1664
	21st to end	Day	8% 13% 4 9% 6% 5% 5% 4 5% 7% 34%	1451
March	1st to 10th	Day	11% 12% 4 8% 5% 5% 4 3 5% 7% 37%	3344
	11th to 20th	Day	9% 8% 3 8% 5% 4 5% 4 6% 8% 40%	3480
	21st to end	Day	19% 12% 4 10% 6% 5% 4 4 5% 6% 25%	3863
April	1st to 10th	Day	17% 10% 3 9% 5% 5% 5% 3 5% 6% 34%	2280
	11th to 20th	Day	19% 11% 4 8% 5% 4 4 3 5% 6% 31%	2295
	21st to end	Day	21% 10% 3 8% 4 5% 4 3 4 6% 32%	2470
May	1st to 10th	Day	18% 7% 2 6% 5% 5% 4 3 5% 6% 39%	4305
	11th to 20th	Day	15% 6% 2 6% 4 4 4 4 6% 6% 43%	4399
	21st to end	Day	17% 7% 3 8% 5% 5% 5% 4 6% 8% 32%	4824
June	1st to 10th	Day	11% 5% 2 5% 4 4 5% 4 7% 8% 45%	2660
	11th to 20th	Day	13% 6% 2 7% 5% 4 5% 4 6% 8% 38%	2825
	21st to end	Day	10% 5% 2 6% 5% 5% 6% 5% 7% 10% 38%	2850
July	1st to 10th	Day	9% 4 2 6% 5% 5% 5% 5% 8% 11% 39%	4750
	11th to 20th	Day	6% 4 1 4 3 4 5% 4 7% 10% 54%	4471
	21st to end	Day	7% 5% 2 5% 4 4 5% 5% 7% 10% 49%	4813
August	1st to 10th	Day	12% 5% 2 5% 4 4 5% 4 7% 8% 44%	4118
	11th to 20th	Day	12% 5% 2 7% 5% 5% 5% 5% 6% 9% 40%	4041
	21st to end	Day	13% 7% 2 7% 4 4 4 3 5% 7% 42%	4372
September	1st to 10th	Day	8% 5% 2 6% 4 5% 4 4 6% 9% 45%	2280
	11th to 20th	Day	11% 6% 2 6% 4 4 4 3 6% 7% 46%	2250
	21st to end	Day	14% 8% 2 6% 4 5% 3 3 6% 7% 43%	2000
October	1st to 10th	Day	17% 8% 2 7% 4 4 4 4 6% 7% 38%	1900
	11th to 20th	Day	15% 11% 3 8% 5% 5% 5% 4 4 6% 36%	1900
	21st to end	Day	19% 12% 3 8% 4 3 4 3 4 6% 33%	2043
November	1st to 10th	Day	14% 12% 4 11% 6% 4 4 3 5% 5% 32%	1605
	11th to 20th	Day	12% 15% 7% 12% 7% 5% 4 4 5% 5% 25%	1520
	21st to end	Day	13% 13% 4 8% 6% 4 5% 4 6% 7% 30%	1520
December	1st to 10th	Day	10% 16% 5% 12% 8% 6% 6% 4 5% 6% 23%	1520
	11th to 20th	Day	11% 14% 5% 12% 7% 5% 5% 4 6% 5% 26%	1918
	21st to end	Day	22% 19% 5% 10% 7% 4 4 3 4 4 18%	2783
January	1st to 10th	Night	11% 11% 5% 13% 7% 5% 4 3 5% 6% 30%	4428
	11th to 20th	Night	6% 10% 5% 13% 9% 8% 9% 6% 7% 7% 22%	4440
	21st to end	Night	9% 19% 7% 14% 6% 4 4 4 5% 5% 24%	4582
February	1st to 10th	Night	6% 10% 5% 10% 6% 5% 5% 4 5% 7% 37%	2470
	11th to 20th	Night	6% 10% 4 9% 6% 6% 4 4 6% 7% 38%	2403
	21st to end	Night	11% 10% 4 8% 5% 5% 5% 3 6% 7% 35%	2002
March	1st to 10th	Night	8% 9% 3 7% 5% 4 4 3 4 6% 47%	3524
	11th to 20th	Night	8% 8% 3 9% 6% 5% 6% 4 6% 6% 40%	3480
	21st to end	Night	22% 12% 4 11% 5% 4 3 2 4 5% 29%	3767
April	1st to 10th	Night	16% 11% 3 6% 4 4 4 4 5% 5% 37%	1900
	11th to 20th	Night	19% 10% 4 7% 4 4 3 2 5% 4 37%	1830
	21st to end	Night	19% 9% 3 7% 4 4 4 5% 5% 7% 33%	1710
May	1st to 10th	Night	14% 9% 3 7% 5% 4 3 3 5% 6% 40%	2600
	11th to 20th	Night	14% 5% 2 5% 3 3 3 3 5% 8% 48%	2506
	21st to end	Night	14% 8% 3 7% 4 4 4 4 7% 7% 38%	2743
June	1st to 10th	Night	11% 5% 2 5% 4 5% 5% 3 7% 8% 45%	1520
	11th to 20th	Night	11% 6% 2 6% 4 5% 5% 4 6% 7% 45%	1349
	21st to end	Night	9% 4 2 6% 4 5% 4 4 6% 8% 48%	1330
July	1st to 10th	Night	10% 4 1 4 4 4 5% 4 7% 11% 46%	2220
	11th to 20th	Night	4 3 1 4 3 3 4 3 6% 8% 60%	2494
	21st to end	Night	5% 3 2 5% 4 4 4 4 5% 8% 56%	2750
August	1st to 10th	Night	10% 5% 2 6% 3 4 4 4 5% 8% 51%	2818
	11th to 20th	Night	13% 5% 2 5% 3 3 3 4 7% 7% 48%	2798
	21st to end	Night	13% 7% 3 6% 4 4 4 4 6% 9% 42%	3288
September	1st to 10th	Night	8% 4 2 5% 3 4 3 4 5% 8% 54%	1900
	11th to 20th	Night	8% 5% 1 4 4 4 4 3 5% 8% 52%	1928
	21st to end	Night	14% 5% 2 5% 4 4 4 2 5% 7% 49%	2161
October	1st to 10th	Night	14% 7% 2 6% 4 4 4 3 4 6% 47%	2280
	11th to 20th	Night	14% 10% 3 6% 4 4 4 4 5% 6% 39%	2280
	21st to end	Night	17% 11% 4 10% 4 4 3 3 5% 5% 34%	2554
November	1st to 10th	Night	14% 9% 3 9% 5% 5% 4 4 5% 6% 35%	2692
	11th to 20th	Night	13% 11% 5% 10% 7% 5% 5% 4 5% 6% 29%	2667
	21st to end	Night	12% 9% 4 8% 6% 5% 5% 5% 6% 7% 34%	2660
December	1st to 10th	Night	9% 13% 4 13% 7% 6% 6% 4 6% 7% 26%	2660
	11th to 20th	Night	10% 15% 5% 11% 6% 5% 6% 4 6% 6% 25%	3279
	21st to end	Night	23% 18% 5% 9% 4 3 3 2 4 5% 22%	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	60% 5% 10% 19% 6%	2528
	11th to 20th	Day	60% 7% 11% 17% 5%	2530
	21st to end	Day	61% 7% 11% 16% 5%	3081
February	1st to 10th	Day	50% 5% 11% 23% 10% 2	1710
	11th to 20th	Day	46% 6% 14% 25% 8% 1	1673
	21st to end	Day	48% 6% 12% 20% 12% 1	1451
March	1st to 10th	Day	47% 6% 14% 24% 10%	3344
	11th to 20th	Day	40% 6% 13% 30% 10% 1	3480
	21st to end	Day	59% 7% 10% 20% 5% 1	3863
April	1st to 10th	Day	50% 5% 11% 19% 13% 1	2280
	11th to 20th	Day	54% 5% 9% 19% 12% 1	2295
	21st to end	Day	54% 6% 11% 20% 10%	2470
May	1st to 10th	Day	44% 6% 12% 23% 13% 1	4344
	11th to 20th	Day	39% 7% 14% 26% 12% 2	4403
	21st to end	Day	46% 8% 13% 23% 9% 1	4837
June	1st to 10th	Day	35% 7% 16% 30% 10% 1	2660
	11th to 20th	Day	42% 8% 14% 22% 14% 1	2825
	21st to end	Day	36% 10% 18% 26% 9% 1	2850
July	1st to 10th	Day	35% 10% 19% 23% 13% 1	4676
	11th to 20th	Day	24% 7% 17% 36% 15% 1	4395
	21st to end	Day	28% 8% 17% 31% 15% 1	4662
August	1st to 10th	Day	35% 7% 13% 29% 14% 2	4103
	11th to 20th	Day	39% 6% 14% 32% 9%	4080
	21st to end	Day	41% 6% 16% 24% 12% 1	4371
September	1st to 10th	Day	34% 7% 15% 35% 10%	2280
	11th to 20th	Day	37% 7% 18% 30% 8%	2250
	21st to end	Day	40% 6% 13% 32% 9% 1	2000
October	1st to 10th	Day	34% 4 12% 33% 16% 1	3160
	11th to 20th	Day	39% 5% 12% 26% 17% 2	3140
	21st to end	Day	49% 4 16% 24% 7%	3345
November	1st to 10th	Day	52% 7% 11% 19% 10% 1	1605
	11th to 20th	Day	61% 5% 13% 14% 6% 1	1520
	21st to end	Day	53% 6% 16% 18% 5% 2	1520
December	1st to 10th	Day	62% 5% 14% 14% 5%	1520
	11th to 20th	Day	59% 7% 14% 16% 4	1915
	21st to end	Day	69% 5% 8% 11% 7%	2783
January	1st to 10th	Night	53% 6% 12% 21% 7% 1	4428
	11th to 20th	Night	58% 7% 14% 14% 6% 1	4440
	21st to end	Night	61% 6% 9% 18% 5% 1	4582
February	1st to 10th	Night	46% 6% 12% 23% 12% 1	2470
	11th to 20th	Night	43% 7% 13% 25% 10% 2	2404
	21st to end	Night	47% 6% 12% 22% 12% 1	2002
March	1st to 10th	Night	39% 6% 13% 24% 17% 2	3524
	11th to 20th	Night	42% 6% 11% 27% 15%	3480
	21st to end	Night	60% 4 9% 17% 9% 1	3767
April	1st to 10th	Night	47% 6% 9% 20% 16% 2	1900
	11th to 20th	Night	50% 5% 7% 21% 16% 2	1830
	21st to end	Night	49% 6% 10% 21% 13% 2	1710
May	1st to 10th	Night	44% 6% 11% 23% 15% 1	2626
	11th to 20th	Night	34% 6% 11% 27% 19% 3	2507
	21st to end	Night	42% 7% 13% 24% 13% 1	2751
June	1st to 10th	Night	36% 7% 16% 28% 12% 3	1520
	11th to 20th	Night	36% 7% 15% 23% 17% 2	1349
	21st to end	Night	32% 8% 15% 30% 13% 3	1330
July	1st to 10th	Night	31% 8% 21% 24% 14% 1	2185
	11th to 20th	Night	20% 6% 13% 41% 17% 2	2448
	21st to end	Night	25% 6% 15% 36% 16% 2	2662
August	1st to 10th	Night	32% 6% 14% 29% 16% 3	2809
	11th to 20th	Night	33% 6% 14% 35% 11% 1	2825
	21st to end	Night	39% 7% 15% 27% 10% 1	3288
September	1st to 10th	Night	27% 7% 16% 35% 15% 1	1900
	11th to 20th	Night	31% 6% 18% 32% 13%	1928
	21st to end	Night	35% 5% 14% 33% 12% 1	2161
October	1st to 10th	Night	26% 3 8% 36% 23% 4	3800
	11th to 20th	Night	36% 5% 12% 27% 19% 1	3779
	21st to end	Night	47% 4 13% 23% 12%	4202
November	1st to 10th	Night	48% 6% 12% 23% 9% 2	2692
	11th to 20th	Night	56% 5% 14% 15% 9%	2667
	21st to end	Night	48% 8% 18% 20% 6% 1	2660
December	1st to 10th	Night	56% 7% 14% 17% 5% 1	2660
	11th to 20th	Night	57% 7% 12% 16% 5% 2	3281
	21st to end	Night	65% 5% 10% 15% 5%	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	17% 11% 33% 27% 11% 3	270
	11th to 20th	Day	15% 9% 39% 31% 6%	270
	21st to end	Day	14% 7% 37% 25% 15% 1	297
February	1st to 10th	Day	17% 13% 43% 20% 6% 1	270
	11th to 20th	Day	12% 21% 40% 19% 6% 2	270
	21st to end	Day	17% 11% 42% 26% 4	225
March	1st to 10th	Day	18% 13% 39% 22% 6% 2	270
	11th to 20th	Day	17% 10% 39% 22% 10% 1	270
	21st to end	Day	26% 12% 27% 22% 10% 2	321
April	1st to 10th	Day	23% 13% 32% 26% 5% 1	460
	11th to 20th	Day	27% 11% 28% 24% 9% 1	493
	21st to end	Day	26% 7% 31% 22% 10% 3	650
May	1st to 10th	Day	21% 11% 30% 27% 9% 2	653
	11th to 20th	Day	18% 13% 26% 28% 11% 4	675
	21st to end	Day	18% 8% 26% 28% 16% 4	734
June	1st to 10th	Day	12% 7% 28% 32% 18% 5%	680
	11th to 20th	Day	14% 9% 34% 30% 12% 2	680
	21st to end	Day	13% 7% 29% 30% 14% 7%	680
July	1st to 10th	Day	8% 4 22% 33% 23% 10%	671
	11th to 20th	Day	9% 6% 26% 30% 21% 9%	668
	21st to end	Day	7% 5% 26% 33% 21% 7%	739
August	1st to 10th	Day	11% 5% 22% 35% 22% 5%	676
	11th to 20th	Day	14% 6% 20% 29% 25% 6%	665
	21st to end	Day	13% 8% 23% 30% 21% 4	653
September	1st to 10th	Day	10% 7% 30% 31% 17% 4	490
	11th to 20th	Day	10% 6% 29% 31% 21% 3	460
	21st to end	Day	19% 14% 27% 22% 13% 5%	300
October	1st to 10th	Day	19% 9% 30% 25% 11% 6%	300
	11th to 20th	Day	15% 18% 35% 26% 6%	300
	21st to end	Day	25% 12% 38% 17% 6%	330
November	1st to 10th	Day	21% 11% 36% 23% 8% 1	300
	11th to 20th	Day	16% 16% 41% 20% 6%	270
	21st to end	Day	21% 15% 37% 24% 3	270
December	1st to 10th	Day	16% 13% 39% 22% 10%	270
	11th to 20th	Day	19% 15% 36% 25% 4	270
	21st to end	Day	31% 10% 32% 24% 2 1	297
January	1st to 10th	Night	13% 10% 37% 31% 9% 1	950
	11th to 20th	Night	15% 8% 38% 31% 8% 1	950
	21st to end	Night	15% 10% 37% 29% 8% 1	1045
February	1st to 10th	Night	11% 9% 39% 30% 9% 1	950
	11th to 20th	Night	10% 13% 42% 26% 9% 1	929
	21st to end	Night	15% 11% 36% 29% 9% 1	746
March	1st to 10th	Night	15% 12% 37% 26% 9% 1	641
	11th to 20th	Night	17% 10% 40% 26% 6%	570
	21st to end	Night	22% 11% 27% 28% 9% 3	627
April	1st to 10th	Night	21% 11% 36% 26% 6%	570
	11th to 20th	Night	25% 8% 30% 29% 8% 1	563
	21st to end	Night	24% 6% 30% 30% 9% 1	570
May	1st to 10th	Night	18% 9% 33% 31% 8% 1	570
	11th to 20th	Night	17% 7% 34% 31% 10% 2	561
	21st to end	Night	16% 6% 27% 36% 16%	617
June	1st to 10th	Night	13% 5% 25% 39% 17% 1	570
	11th to 20th	Night	12% 5% 32% 39% 12%	570
	21st to end	Night	12% 5% 22% 41% 19% 1	570
July	1st to 10th	Night	5% 3 21% 43% 25% 3	555
	11th to 20th	Night	8% 4 24% 39% 23% 2	552
	21st to end	Night	6% 3 21% 46% 22% 2	624
August	1st to 10th	Night	7% 3 17% 52% 19% 2	567
	11th to 20th	Night	14% 3 19% 35% 26% 3	564
	21st to end	Night	12% 4 22% 37% 23% 2	627
September	1st to 10th	Night	11% 4 23% 39% 20% 3	570
	11th to 20th	Night	11% 4 28% 36% 20% 2	570
	21st to end	Night	16% 8% 30% 30% 14% 1	641
October	1st to 10th	Night	19% 8% 29% 30% 12% 1	760
	11th to 20th	Night	20% 11% 33% 30% 6% 1	760
	21st to end	Night	23% 11% 30% 29% 6%	836
November	1st to 10th	Night	20% 11% 29% 31% 9%	936
	11th to 20th	Night	19% 12% 32% 28% 9% 1	953
	21st to end	Night	16% 13% 37% 26% 7%	950
December	1st to 10th	Night	16% 11% 34% 31% 8% 1	950
	11th to 20th	Night	20% 10% 35% 28% 7% 1	950
	21st to end	Night	25% 10% 33% 25% 6% 1	1045

Page generated at 2024-11-08 05:44:51. Version ac07

Copyright © 2024 Attilla Danko.