The normal date of the onset of the southwest monsoon over India is 1 June. The monsoon takes about a month and a half to travel from Kerala to west Rajasthan and it does not advance into the country at a constant speed. If you want to know how the southwest monsoon has been progressing this year over India, the best way is to visit the official web site of the India Meteorological Department (IMD) at www.imd.ernet.in or www.imd.gov.in and click on ‘Progress of Monsoon’ on the home page. Or you can go directly to www.imd.gov.in/section/nhac/dynamic/mon-prog.htm. Here you will see a map of India that gives the normal dates of onset over various places in India and also where the normal limit of the monsoon lies currently. This map gets updated as and when the southwest monsoon advances further and it will remain static after the monsoon has covered all of India.

It does not necessarily mean that it would be raining everywhere to the south or east of this northern limit of the monsoon. To know what is actually happening over the southwest monsoon region, you can click on ‘Daily Monsoon Report’ on the home page of the IMD web site. Alternatively, you can go straight to http://www.imd.gov.in/section/nhac/dynamic/SPLNEW.HTM. On this page, you will get to know the chief features of the prevailing meteorological situation over India and 3-day rainfall forecasts for various regions. This page gets updated every day.

For those who are interested in the statistical analysis of monsoon rainfall over India, ‘Monsoon On Line (MOL)’ is the most appropriate web site. It can be reached through the web site of the Indian Institute of Tropical Meteorology, Pune, at www.tropmet.res.in or directly at http://www.tropmet.res.in/%7Ekolli/MOL/Monsoon/frameindex.html. The MOL home page shows a Monsoon 2007 Progress Card that gives the All-India Summer Monsoon Rainfall from 1 June 2007 to the current week: Actual, Normal, Departure and Proportion of Seasonal Normal. Other pages of MOL give an analysis of the rainfall over India as various time series (All-India Daily, All-India Weekly, Sub-divisional Weekly and Station Daily) and in the form of different rainfall maps (Weekly, Weekly Cumulative and Seasonal). The charts and maps of Monsoon On Line are based upon near-real time data and information from IMD. However, MOL displays a map of the latest precipitation estimate for south and southeast Asia that is generated by the NOAA Climate Prediction Center from satellite and rain-gauge data.

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