Weyburn
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weyburn clear sky chart from 2005-11-06 to 2024-10-20.

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	9% 8% 3 8% 5% 5% 5% 4 6% 8% 38%	101946
	Night	8% 9% 4 9% 6% 5% 5% 4 6% 8% 38%	96911
Transparency	Day	42% 8% 15% 25% 9% 1	101690
	Night	43% 7% 16% 23% 10% 1	96758
Seeing	Day	12% 9% 30% 30% 16% 3	16161
	Night	12% 7% 32% 35% 12% 1	25709

By Month

Percentage Cloud Cover SW (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	7% 13% 5% 14% 8% 8% 7% 5% 6% 7% 19%	2538
	11th to 20th	Day	6% 8% 4 13% 10% 11% 10% 9% 8% 6% 15%	2540
	21st to end	Day	5% 11% 5% 12% 8% 6% 5% 4 5% 6% 31%	2794
February	1st to 10th	Day	9% 14% 5% 12% 9% 6% 8% 5% 6% 5% 22%	1550
	11th to 20th	Day	7% 12% 6% 11% 9% 8% 8% 6% 6% 7% 22%	1677
	21st to end	Day	5% 11% 5% 11% 9% 8% 6% 6% 7% 7% 24%	1570
March	1st to 10th	Day	8% 14% 6% 13% 7% 5% 7% 4 5% 6% 25%	3130
	11th to 20th	Day	5% 12% 5% 13% 7% 5% 5% 4 6% 7% 30%	3257
	21st to end	Day	7% 13% 6% 15% 7% 6% 5% 4 6% 8% 22%	4161
April	1st to 10th	Day	7% 8% 2 7% 6% 5% 5% 4 7% 8% 40%	2280
	11th to 20th	Day	13% 14% 3 9% 5% 5% 5% 4 6% 7% 28%	2293
	21st to end	Day	13% 10% 2 7% 5% 5% 4 4 5% 8% 37%	2559
May	1st to 10th	Day	17% 10% 3 7% 4 4 4 4 6% 8% 34%	4430
	11th to 20th	Day	11% 7% 2 7% 5% 5% 5% 5% 7% 9% 36%	4388
	21st to end	Day	13% 6% 2 7% 5% 5% 6% 5% 6% 8% 37%	4939
June	1st to 10th	Day	13% 5% 2 6% 5% 4 5% 4 7% 9% 40%	2850
	11th to 20th	Day	15% 7% 2 7% 5% 5% 5% 4 6% 8% 35%	2935
	21st to end	Day	10% 5% 2 5% 5% 4 5% 5% 8% 9% 44%	3040
July	1st to 10th	Day	6% 4 2 5% 5% 5% 5% 5% 8% 10% 46%	4738
	11th to 20th	Day	4 3 1 4 3 4 5% 4 7% 9% 56%	4430
	21st to end	Day	4 3 1 4 3 4 4 4 7% 8% 58%	4802
August	1st to 10th	Day	9% 4 2 5% 4 4 4 4 6% 8% 49%	4411
	11th to 20th	Day	6% 4 1 5% 4 5% 5% 4 6% 9% 51%	4343
	21st to end	Day	9% 4 2 5% 4 4 4 3 4 8% 54%	4218
September	1st to 10th	Day	11% 5% 2 5% 3 3 4 4 5% 8% 50%	2280
	11th to 20th	Day	13% 7% 3 6% 4 3 4 3 5% 7% 45%	2235
	21st to end	Day	12% 6% 2 6% 3 4 3 3 5% 8% 49%	2090
October	1st to 10th	Day	14% 10% 3 6% 3 4 3 2 6% 7% 41%	1920
	11th to 20th	Day	10% 8% 3 8% 4 3 4 4 7% 8% 42%	1791
	21st to end	Day	10% 13% 5% 10% 5% 3 4 4 5% 6% 34%	1782
November	1st to 10th	Day	12% 14% 4 10% 6% 5% 5% 4 5% 5% 30%	1625
	11th to 20th	Day	7% 13% 4 12% 8% 6% 5% 4 5% 6% 30%	1520
	21st to end	Day	7% 15% 6% 10% 6% 6% 5% 4 5% 7% 29%	1361
December	1st to 10th	Day	7% 15% 6% 13% 10% 5% 5% 4 6% 8% 22%	1330
	11th to 20th	Day	7% 16% 5% 14% 8% 7% 6% 4 6% 9% 19%	1683
	21st to end	Day	6% 7% 3 9% 5% 5% 5% 5% 7% 7% 42%	2456
January	1st to 10th	Night	4 12% 5% 12% 9% 5% 5% 5% 6% 7% 29%	4417
	11th to 20th	Night	4 7% 5% 14% 10% 10% 10% 6% 7% 6% 21%	4430
	21st to end	Night	6% 12% 5% 10% 7% 5% 6% 4 7% 8% 30%	4873
February	1st to 10th	Night	7% 13% 5% 11% 8% 7% 6% 6% 6% 8% 23%	2646
	11th to 20th	Night	6% 12% 4 11% 8% 7% 6% 5% 6% 7% 27%	2389
	21st to end	Night	4 10% 4 11% 7% 6% 6% 4 6% 8% 34%	1884
March	1st to 10th	Night	6% 11% 5% 12% 7% 5% 4 4 7% 9% 30%	3734
	11th to 20th	Night	5% 9% 4 9% 6% 5% 6% 5% 7% 9% 37%	3712
	21st to end	Night	7% 13% 7% 14% 6% 5% 4 3 5% 7% 30%	3480
April	1st to 10th	Night	6% 9% 3 7% 4 4 4 4 6% 8% 45%	1900
	11th to 20th	Night	13% 12% 4 9% 5% 4 4 4 7% 6% 32%	1835
	21st to end	Night	12% 9% 3 8% 5% 4 4 5% 6% 7% 38%	1619
May	1st to 10th	Night	18% 10% 3 7% 3 4 4 2 5% 6% 38%	2540
	11th to 20th	Night	11% 7% 2 6% 5% 4 5% 4 6% 8% 42%	2517
	21st to end	Night	14% 6% 2 6% 5% 5% 5% 5% 6% 9% 38%	2647
June	1st to 10th	Night	12% 4 2 5% 4 4 4 3 6% 8% 47%	1330
	11th to 20th	Night	13% 6% 2 6% 5% 3 3 4 5% 10% 44%	1237
	21st to end	Night	9% 4 2 6% 4 3 3 5% 7% 9% 47%	1140
July	1st to 10th	Night	5% 3 1 5% 4 4 4 4 8% 13% 48%	2204
	11th to 20th	Night	6% 3 1 5% 3 3 5% 4 6% 7% 56%	2540
	21st to end	Night	3 2 1 4 3 3 3 3 4 7% 67%	2761
August	1st to 10th	Night	8% 4 2 5% 4 5% 4 3 5% 8% 53%	2528
	11th to 20th	Night	5% 3 1 4 3 3 4 3 6% 9% 57%	2496
	21st to end	Night	6% 3 2 4 3 3 3 4 6% 9% 56%	3446
September	1st to 10th	Night	9% 4 2 5% 3 3 4 3 5% 7% 55%	1900
	11th to 20th	Night	11% 5% 2 5% 4 4 4 3 5% 7% 50%	1944
	21st to end	Night	12% 6% 2 6% 4 4 4 4 5% 7% 47%	2090
October	1st to 10th	Night	12% 8% 3 7% 4 4 3 3 5% 6% 44%	2256
	11th to 20th	Night	8% 9% 3 6% 4 4 4 3 5% 8% 46%	2355
	21st to end	Night	10% 12% 4 10% 5% 5% 4 3 5% 7% 36%	2574
November	1st to 10th	Night	12% 14% 4 10% 6% 4 4 3 5% 6% 34%	2452
	11th to 20th	Night	7% 11% 4 11% 7% 7% 5% 4 7% 7% 29%	2660
	21st to end	Night	7% 12% 5% 12% 6% 5% 4 4 5% 7% 32%	2816
December	1st to 10th	Night	7% 11% 6% 12% 8% 7% 5% 4 6% 7% 27%	2850
	11th to 20th	Night	7% 14% 6% 13% 8% 6% 5% 4 6% 6% 24%	3514
	21st to end	Night	5% 8% 3 9% 6% 5% 5% 5% 6% 8% 41%	5195

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	61% 8% 15% 13% 4	2539
	11th to 20th	Day	64% 7% 14% 10% 4	2540
	21st to end	Day	52% 7% 12% 25% 4	2794
February	1st to 10th	Day	62% 5% 11% 16% 6%	1550
	11th to 20th	Day	60% 7% 11% 12% 10%	1686
	21st to end	Day	55% 7% 13% 15% 8% 1	1570
March	1st to 10th	Day	58% 7% 16% 16% 3	3130
	11th to 20th	Day	50% 9% 17% 18% 5%	3257
	21st to end	Day	54% 10% 14% 16% 6%	4161
April	1st to 10th	Day	39% 8% 16% 26% 10% 1	2280
	11th to 20th	Day	53% 7% 14% 18% 8% 1	2296
	21st to end	Day	45% 7% 17% 23% 8% 1	2559
May	1st to 10th	Day	45% 8% 15% 23% 8% 1	4430
	11th to 20th	Day	40% 10% 13% 23% 14%	4392
	21st to end	Day	40% 11% 14% 28% 8% 1	4939
June	1st to 10th	Day	39% 8% 16% 26% 9% 2	2850
	11th to 20th	Day	44% 9% 16% 19% 10% 1	2935
	21st to end	Day	34% 9% 19% 28% 9% 1	3040
July	1st to 10th	Day	30% 10% 23% 29% 7% 1	4668
	11th to 20th	Day	22% 7% 16% 39% 15% 1	4355
	21st to end	Day	21% 7% 14% 38% 16% 5%	4651
August	1st to 10th	Day	31% 7% 17% 25% 18% 1	4396
	11th to 20th	Day	28% 7% 19% 36% 9% 1	4385
	21st to end	Day	29% 6% 14% 40% 10% 1	4217
September	1st to 10th	Day	31% 6% 15% 29% 16% 3	2280
	11th to 20th	Day	39% 5% 14% 27% 11% 3	2235
	21st to end	Day	35% 5% 12% 31% 15% 2	2090
October	1st to 10th	Day	43% 5% 14% 27% 10% 1	1920
	11th to 20th	Day	39% 5% 16% 29% 10% 1	1791
	21st to end	Day	50% 6% 17% 19% 7%	1782
November	1st to 10th	Day	55% 6% 14% 18% 6% 1	1625
	11th to 20th	Day	54% 7% 15% 15% 8% 1	1520
	21st to end	Day	56% 8% 16% 15% 5%	1361
December	1st to 10th	Day	60% 8% 11% 16% 5%	1330
	11th to 20th	Day	61% 7% 17% 11% 3	1680
	21st to end	Day	38% 6% 12% 26% 16% 2	2456
January	1st to 10th	Night	51% 7% 17% 19% 6%	4417
	11th to 20th	Night	60% 7% 16% 14% 4	4430
	21st to end	Night	49% 8% 19% 19% 4	4873
February	1st to 10th	Night	56% 7% 12% 17% 7%	2646
	11th to 20th	Night	54% 6% 13% 16% 10% 1	2390
	21st to end	Night	47% 6% 15% 22% 10%	1884
March	1st to 10th	Night	49% 7% 19% 21% 4	3734
	11th to 20th	Night	41% 8% 24% 22% 5%	3712
	21st to end	Night	52% 8% 14% 18% 8%	3480
April	1st to 10th	Night	36% 6% 15% 24% 18% 1	1900
	11th to 20th	Night	50% 5% 12% 21% 11% 2	1835
	21st to end	Night	42% 7% 13% 25% 11% 1	1619
May	1st to 10th	Night	45% 6% 13% 22% 12% 1	2540
	11th to 20th	Night	37% 9% 14% 21% 17% 2	2518
	21st to end	Night	38% 10% 13% 27% 11% 1	2647
June	1st to 10th	Night	33% 7% 18% 27% 13% 3	1330
	11th to 20th	Night	36% 9% 19% 20% 14% 3	1237
	21st to end	Night	31% 9% 18% 32% 9%	1140
July	1st to 10th	Night	26% 10% 27% 29% 7% 1	2166
	11th to 20th	Night	25% 7% 14% 38% 15% 2	2492
	21st to end	Night	18% 4 16% 36% 18% 8%	2674
August	1st to 10th	Night	30% 6% 15% 31% 16% 1	2520
	11th to 20th	Night	23% 5% 19% 39% 13% 1	2520
	21st to end	Night	24% 5% 19% 34% 16% 2	3446
September	1st to 10th	Night	27% 6% 11% 30% 23% 3	1900
	11th to 20th	Night	33% 6% 14% 26% 18% 2	1944
	21st to end	Night	36% 5% 12% 29% 15% 2	2090
October	1st to 10th	Night	41% 5% 15% 26% 12% 1	2256
	11th to 20th	Night	37% 5% 15% 30% 12% 1	2355
	21st to end	Night	47% 4 15% 24% 8% 1	2574
November	1st to 10th	Night	52% 6% 14% 18% 9% 2	2452
	11th to 20th	Night	52% 8% 17% 17% 6% 1	2660
	21st to end	Night	50% 7% 19% 18% 6%	2816
December	1st to 10th	Night	55% 6% 16% 16% 6%	2850
	11th to 20th	Night	59% 6% 14% 15% 6%	3516
	21st to end	Night	39% 7% 12% 22% 15% 5%	5195

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	9% 7% 35% 29% 16% 4	270
	11th to 20th	Day	9% 10% 33% 34% 13% 1	270
	21st to end	Day	11% 11% 34% 33% 10% 1	297
February	1st to 10th	Day	16% 8% 35% 32% 9%	270
	11th to 20th	Day	8% 7% 39% 29% 14% 3	270
	21st to end	Day	4 7% 32% 36% 19% 2	225
March	1st to 10th	Day	16% 8% 36% 26% 12% 2	270
	11th to 20th	Day	12% 14% 33% 27% 12% 3	318
	21st to end	Day	11% 13% 32% 27% 14% 2	506
April	1st to 10th	Day	11% 14% 40% 27% 7% 1	460
	11th to 20th	Day	20% 14% 29% 28% 8% 1	494
	21st to end	Day	15% 10% 31% 28% 15% 1	650
May	1st to 10th	Day	13% 9% 27% 32% 16% 3	653
	11th to 20th	Day	13% 10% 27% 26% 17% 7%	675
	21st to end	Day	16% 9% 27% 25% 19% 4	734
June	1st to 10th	Day	12% 11% 31% 26% 17% 4	680
	11th to 20th	Day	17% 10% 32% 26% 13% 2	680
	21st to end	Day	10% 9% 24% 33% 20% 5%	680
July	1st to 10th	Day	8% 4 23% 37% 24% 5%	671
	11th to 20th	Day	6% 6% 29% 34% 21% 5%	668
	21st to end	Day	4 5% 29% 34% 20% 9%	739
August	1st to 10th	Day	9% 6% 22% 37% 20% 7%	676
	11th to 20th	Day	9% 5% 21% 33% 24% 7%	665
	21st to end	Day	9% 7% 25% 35% 20% 5%	564
September	1st to 10th	Day	12% 9% 30% 31% 14% 4	490
	11th to 20th	Day	18% 11% 26% 27% 17% 1	445
	21st to end	Day	17% 8% 29% 28% 16% 1	300
October	1st to 10th	Day	20% 8% 29% 23% 18% 3	300
	11th to 20th	Day	11% 11% 36% 25% 15% 3	297
	21st to end	Day	18% 13% 35% 26% 7% 1	297
November	1st to 10th	Day	23% 9% 31% 22% 14% 2	270
	11th to 20th	Day	12% 13% 34% 30% 9% 1	270
	21st to end	Day	10% 11% 34% 33% 11% 1	270
December	1st to 10th	Day	13% 8% 33% 30% 12% 4	270
	11th to 20th	Day	11% 16% 39% 26% 6% 1	270
	21st to end	Day	11% 7% 32% 34% 14% 3	297
January	1st to 10th	Night	8% 10% 37% 32% 12% 1	950
	11th to 20th	Night	13% 12% 33% 33% 9%	950
	21st to end	Night	11% 11% 37% 32% 9% 1	1045
February	1st to 10th	Night	13% 8% 33% 33% 12% 1	936
	11th to 20th	Night	11% 7% 36% 34% 10% 2	744
	21st to end	Night	5% 7% 29% 38% 18% 3	628
March	1st to 10th	Night	11% 8% 33% 35% 12% 2	760
	11th to 20th	Night	10% 8% 36% 32% 13% 2	760
	21st to end	Night	14% 7% 29% 35% 15% 1	630
April	1st to 10th	Night	8% 10% 36% 36% 11%	570
	11th to 20th	Night	18% 8% 36% 31% 6% 1	563
	21st to end	Night	16% 9% 34% 31% 9% 1	570
May	1st to 10th	Night	16% 5% 26% 40% 13% 1	570
	11th to 20th	Night	14% 4 30% 36% 14% 1	561
	21st to end	Night	17% 8% 25% 32% 17% 1	617
June	1st to 10th	Night	15% 6% 28% 35% 16%	570
	11th to 20th	Night	15% 4 35% 31% 14%	477
	21st to end	Night	10% 4 28% 42% 16% 1	380
July	1st to 10th	Night	6% 4 23% 47% 19% 1	449
	11th to 20th	Night	6% 4 29% 46% 14% 1	552
	21st to end	Night	4 3 28% 46% 17% 2	624
August	1st to 10th	Night	7% 3 24% 48% 16% 2	567
	11th to 20th	Night	8% 3 23% 42% 22% 2	564
	21st to end	Night	7% 5% 26% 43% 18% 1	627
September	1st to 10th	Night	11% 6% 25% 39% 18% 1	570
	11th to 20th	Night	12% 4 31% 36% 16% 1	570
	21st to end	Night	14% 6% 31% 38% 10% 1	570
October	1st to 10th	Night	16% 8% 27% 35% 13% 1	736
	11th to 20th	Night	13% 8% 29% 38% 12% 1	839
	21st to end	Night	15% 9% 32% 34% 8% 1	990
November	1st to 10th	Night	18% 10% 33% 31% 7% 1	925
	11th to 20th	Night	13% 10% 37% 30% 9% 2	950
	21st to end	Night	13% 11% 37% 32% 8%	950
December	1st to 10th	Night	12% 7% 34% 32% 12% 2	950
	11th to 20th	Night	13% 10% 36% 31% 9% 1	950
	21st to end	Night	13% 7% 33% 33% 12% 2	1045

Page generated at 2024-10-17 11:09:42. Version ac07

Copyright © 2024 Attilla Danko.